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Note: This page contains sample records for the topic "kinetics laser ablation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


1

ablation laser spectrometer  

E-Print Network [OSTI]

ablation laser mass spectrometer molecular beam REMPI laser NREL has designed and developed a combined laser ablation/ pulsed sample introduction/mass spectrometry platform that integrates pyrolysis and/or laser ablation with resonance- enhanced multiphoton ionization (REMPI) time-of-flight mass

2

Single Particle Laser Ablation | EMSL  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Single Particle Laser Ablation Single Particle Laser Ablation Leads No leads are available at this time. Effect of Solar Radiation on the Optical Properties and Molecular...

3

EMSL - Single Particle Laser Ablation  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

single-particle-laser-ablation en Effect of Solar Radiation on the Optical Properties and Molecular Composition of Laboratory Proxies of Atmospheric Brown Carbon http:...

4

Laser ablation based fuel ignition  

DOE Patents [OSTI]

There is provided a method of fuel/oxidizer ignition comprising: (a) application of laser light to a material surface which is absorptive to the laser radiation; (b) heating of the material surface with the laser light to produce a high temperature ablation plume which emanates from the heated surface as an intensely hot cloud of vaporized surface material; and (c) contacting the fuel/oxidizer mixture with the hot ablation cloud at or near the surface of the material in order to heat the fuel to a temperature sufficient to initiate fuel ignition.

Early, James W. (Los Alamos, NM); Lester, Charles S. (San Juan Pueblo, NM)

1998-01-01T23:59:59.000Z

5

Laser ablation based fuel ignition  

DOE Patents [OSTI]

There is provided a method of fuel/oxidizer ignition comprising: (a) application of laser light to a material surface which is absorptive to the laser radiation; (b) heating of the material surface with the laser light to produce a high temperature ablation plume which emanates from the heated surface as an intensely hot cloud of vaporized surface material; and (c) contacting the fuel/oxidizer mixture with the hot ablation cloud at or near the surface of the material in order to heat the fuel to a temperature sufficient to initiate fuel ignition. 3 figs.

Early, J.W.; Lester, C.S.

1998-06-23T23:59:59.000Z

6

Laser ablation in analytical chemistry - A review  

SciTech Connect (OSTI)

Laser ablation is becoming a dominant technology for direct solid sampling in analytical chemistry. Laser ablation refers to the process in which an intense burst of energy delivered by a short laser pulse is used to sample (remove a portion of) a material. The advantages of laser ablation chemical analysis include direct characterization of solids, no chemical procedures for dissolution, reduced risk of contamination or sample loss, analysis of very small samples not separable for solution analysis, and determination of spatial distributions of elemental composition. This review describes recent research to understand and utilize laser ablation for direct solid sampling, with emphasis on sample introduction to an inductively coupled plasma (ICP). Current research related to contemporary experimental systems, calibration and optimization, and fractionation is discussed, with a summary of applications in several areas.

Russo, Richard E.; Mao, Xianglei; Liu, Haichen; Gonzalez, Jhanis; Mao, Samuel S.

2001-10-10T23:59:59.000Z

7

Laser ablated hard coating for microtools  

DOE Patents [OSTI]

Wear-resistant coatings composed of laser ablated hard carbon films, are deposited by pulsed laser ablation using visible light, on instruments such as microscope tips and micro-surgical tools. Hard carbon, known as diamond-like carbon (DLC), films produced by pulsed laser ablation using visible light enhances the abrasion resistance, wear characteristics, and lifetimes of small tools or instruments, such as small, sharp silicon tips used in atomic probe microscopy without significantly affecting the sharpness or size of these devices. For example, a 10--20 nm layer of diamond-like carbon on a standard silicon atomic force microscope (AFM) tip, enables the useful operating life of the tip to be increased by at least twofold. Moreover, the low inherent friction coefficient of the DLC coating leads to higher resolution for AFM tips operating in the contact mode. 12 figs.

McLean, W. II; Balooch, M.; Siekhaus, W.J.

1998-05-05T23:59:59.000Z

8

Laser ablated hard coating for microtools  

DOE Patents [OSTI]

Wear-resistant coatings composed of laser ablated hard carbon films, are deposited by pulsed laser ablation using visible light, on instruments such as microscope tips and micro-surgical tools. Hard carbon, known as diamond-like carbon (DLC), films produced by pulsed laser ablation using visible light enhances the abrasion resistance, wear characteristics, and lifetimes of small tools or instruments, such as small, sharp silicon tips used in atomic probe microscopy without significantly affecting the sharpness or size of these devices. For example, a 10-20 nm layer of diamond-like carbon on a standard silicon atomic force microscope (AFM) tip, enables the useful operating life of the tip to be increased by at least twofold. Moreover, the low inherent friction coefficient of the DLC coating leads to higher resolution for AFM tips operating in the contact mode.

McLean, II, William (Oakland, CA); Balooch, Mehdi (Berkeley, CA); Siekhaus, Wigbert J. (Berkeley, CA)

1998-05-05T23:59:59.000Z

9

Subcellular analysis by laser ablation electrospray ionization mass spectrometry  

DOE Patents [OSTI]

In various embodiments, a method of laser ablation electrospray ionization mass spectrometry (LAESI-MS) may generally comprise micro-dissecting a cell comprising at least one of a cell wall and a cell membrane to expose at least one subcellular component therein, ablating the at least one subcellular component by an infrared laser pulse to form an ablation plume, intercepting the ablation plume by an electrospray plume to form ions, and detecting the ions by mass spectrometry.

Vertes, Akos; Stolee, Jessica A; Shrestha, Bindesh

2014-12-02T23:59:59.000Z

10

Solar cell contact formation using laser ablation  

DOE Patents [OSTI]

The formation of solar cell contacts using a laser is described. A method of fabricating a back-contact solar cell includes forming a poly-crystalline material layer above a single-crystalline substrate. The method also includes forming a dielectric material stack above the poly-crystalline material layer. The method also includes forming, by laser ablation, a plurality of contacts holes in the dielectric material stack, each of the contact holes exposing a portion of the poly-crystalline material layer; and forming conductive contacts in the plurality of contact holes.

Harley, Gabriel; Smith, David; Cousins, Peter

2012-12-04T23:59:59.000Z

11

Solar cell contact formation using laser ablation  

DOE Patents [OSTI]

The formation of solar cell contacts using a laser is described. A method of fabricating a back-contact solar cell includes forming a poly-crystalline material layer above a single-crystalline substrate. The method also includes forming a dielectric material stack above the poly-crystalline material layer. The method also includes forming, by laser ablation, a plurality of contacts holes in the dielectric material stack, each of the contact holes exposing a portion of the poly-crystalline materiat layer; and forming conductive contacts in the plurality of contact holes.

Harley, Gabriel; Smith, David D.; Cousins, Peter John

2014-07-22T23:59:59.000Z

12

Heat-affected zone and ablation rate of copper ablated with femtosecond laser  

SciTech Connect (OSTI)

We describe the experimental and molecular dynamics simulation study of crystalline copper (Cu) ablation using femtosecond lasers. This study is focused on the heat-affected zone after femtosecond laser ablation and the laser ablation rate. As a result of the x-ray diffraction measurement on the ablated surface, the crystallinity of the surface is partially changed from a crystal structure into an amorphous one. At the laser fluences below the ablation threshold, the entire laser energy coupled to the Cu target is absorbed, while during the fluence regime over the threshold fluence, the ablation rate depends on the absorption coefficient, and the residual energy which is not used for the ablation, is left in the Cu substrate. The heat-affected zone at the fluences below the threshold is estimated to be greater than that over the threshold fluence. In addition, the laser ablation of Cu is theoretically investigated by a two-temperature model and molecular dynamics (MD) simulation to explain the heat-affected zone and ablation rate. The MD simulation takes into account the electron temperature and thermal diffusion length calculated by the two-temperature model. Variation in the lattice temperature with time and depth is calculated by the MD simulation coupled with the two-temperature model. The experimental ablation rate and the heat-affected zone are theoretically well explained.

Hirayama, Yoichi; Obara, Minoru [Department of Electronics and Electrical Engineering, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522 (Japan)

2005-03-15T23:59:59.000Z

13

Apparatus for the Laser Ablative Synthesis of Carbon Nanotubes...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Apparatus for the Laser Ablative Synthesis of Carbon Nanotubes Thomas Jefferson National Accelerator Facility Contact TJNAF About This Technology Technology Marketing SummaryThis...

14

E-Print Network 3.0 - aluminium laser ablation Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

laser ablation Search Powered by Explorit Topic List Advanced Search Sample search results for: aluminium laser ablation Page: << < 1 2 3 4 5 > >> 1 Available online at...

15

E-Print Network 3.0 - assisted laser ablation Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Powered by Explorit Topic List Advanced Search Sample search results for: assisted laser ablation Page: << < 1 2 3 4 5 > >> 1 ORIGINAL ARTICLE Ultrashort pulsed laser ablation...

16

Laser Ablation Synthesis and Optical Characterization of Silicon Carbide Nanowires  

E-Print Network [OSTI]

Laser Ablation Synthesis and Optical Characterization of Silicon Carbide Nanowires Wensheng Shi Kong, SAR, China Silicon carbide (SiC) nanowires were synthesized at 900°C by the laser ablation and composite nanostructures,4 have been fabricated by this technique. Silicon carbide (SiC) is a wide

Zheng, Yufeng

17

Femtosecond Laser Ablation of Silicon: Nanoparticles, Doping and Photovoltaics  

E-Print Network [OSTI]

Femtosecond Laser Ablation of Silicon: Nanoparticles, Doping and Photovoltaics A thesis presented Laser Ablation of Silicon: Nanoparticles, Doping and Photovoltaics Eric Mazur Brian R. Tull Abstract irradiated surface layer to the grain boundaries. #12;iv Lastly, we measure the photovoltaic properties

Mazur, Eric

18

Laser ablation loading of a surface-electrode ion trap  

E-Print Network [OSTI]

We demonstrate loading by laser ablation of $^{88}$Sr$^+$ ions into a mm-scale surface-electrode ion trap. The laser used for ablation is a pulsed, frequency-tripled Nd:YAG with pulse energies of 1-10 mJ and durations of 3-5 ns. An additional laser is not required to photoionize the ablated material. The efficiency and lifetime of several candidate materials for the laser ablation target are characterized by measuring the trapped ion fluorescence signal for a number of consecutive loads. Additionally, laser ablation is used to load traps with a trap depth (40 meV) below where electron impact ionization loading is typically successful ($\\gtrsim$ 500 meV).

David R. Leibrandt; Robert J. Clark; Jaroslaw Labaziewicz; Paul Antohi; Waseem Bakr; Kenneth R. Brown; Isaac L. Chuang

2007-06-22T23:59:59.000Z

19

Femtosecond laser ablation of brass in air and liquid media  

SciTech Connect (OSTI)

Laser ablation of brass in air, water, and ethanol was investigated using a femtosecond laser system operating at a wavelength of 785 nm and a pulse width less than 130 fs. Scanning electron and optical microscopy were used to study the efficiency and quality of laser ablation in the three ablation media at two different ablation modes. With a liquid layer thickness of 3 mm above the target, ablation rate was found to be higher in water and ethanol than in air. Ablation under water and ethanol showed cleaner surfaces and less debris re-deposition compared to ablation in air. In addition to spherical particles that are normally formed from re-solidified molten material, micro-scale particles with varying morphologies were observed scattered in the ablated structures (craters and grooves) when ablation was conducted under water. The presence of such particles indicates the presence of a non-thermal ablation mechanism that becomes more apparent when ablation is conducted under water.

Shaheen, M. E. [Great Lakes Institute for Environmental Research (GLIER), University of Windsor, Windsor, Ontario N9B 3P4 (Canada) [Great Lakes Institute for Environmental Research (GLIER), University of Windsor, Windsor, Ontario N9B 3P4 (Canada); Department of Physics, Faculty of Sciences, Tanta University, Tanta (Egypt); Gagnon, J. E.; Fryer, B. J. [Great Lakes Institute for Environmental Research (GLIER), University of Windsor, Windsor, Ontario N9B 3P4 (Canada) [Great Lakes Institute for Environmental Research (GLIER), University of Windsor, Windsor, Ontario N9B 3P4 (Canada); Department of Earth and Environmental Sciences, University of Windsor, Windsor, Ontario N9B 3P4 (Canada)

2013-06-07T23:59:59.000Z

20

Revisiting the interplay between ablation, collisional, and radiative processes during ns-laser ablation  

SciTech Connect (OSTI)

A study of ns-laser ablation is presented, which focuses on the transient behavior of the physical processes that act in and above a copper sample. A dimensionless multiphase collisional radiative model describes the interplay between the ablation, collisional, and radiative mechanisms. Calculations are done for a 6 ns-Nd:YAG laser pulse operating at 532 nm and fluences up to 15 J/cm{sup 2}. Temporal intensity profiles as well as transmissivities are in good agreement with experimental results. It is found that volumetric ablation mechanisms and photo-processes both play an essential role in the onset of ns-laser induced breakdown.

Autrique, D. [Department of Physics and OPTIMAS Research Center, TU Kaiserslautern, 67653 Kaiserslautern (Germany) [Department of Physics and OPTIMAS Research Center, TU Kaiserslautern, 67653 Kaiserslautern (Germany); Department of Chemistry, University of Antwerp, 2610 Wilrijk (Belgium); Gornushkin, I. [Federal Institute for Materials Research and Testing - BAM, 12489 Berlin (Germany)] [Federal Institute for Materials Research and Testing - BAM, 12489 Berlin (Germany); Alexiades, V. [Department of Mathematics, University of Tennessee, Knoxville, Tennessee 37996-1320 (United States)] [Department of Mathematics, University of Tennessee, Knoxville, Tennessee 37996-1320 (United States); Chen, Z.; Bogaerts, A. [Department of Chemistry, University of Antwerp, 2610 Wilrijk (Belgium)] [Department of Chemistry, University of Antwerp, 2610 Wilrijk (Belgium); Rethfeld, B. [Department of Physics and OPTIMAS Research Center, TU Kaiserslautern, 67653 Kaiserslautern (Germany)] [Department of Physics and OPTIMAS Research Center, TU Kaiserslautern, 67653 Kaiserslautern (Germany)

2013-10-21T23:59:59.000Z

Note: This page contains sample records for the topic "kinetics laser ablation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

Plume collimation for laser ablation electrospray ionization mass spectrometry  

DOE Patents [OSTI]

In various embodiments, a device may generally comprise a capillary having a first end and a second end; a laser to emit energy at a sample in the capillary to ablate the sample and generate an ablation plume in the capillary; an electrospray apparatus to generate an electrospray plume to intercept the ablation plume to produce ions; and a mass spectrometer having an ion transfer inlet to capture the ions. The ablation plume may comprise a collimated ablation plume. The device may comprise a flow cytometer. Methods of making and using the same are also described.

Vertes, Akos; Stolee, Jessica A.

2014-09-09T23:59:59.000Z

22

Surface Decontamination Using Laser Ablation Process - 12032  

SciTech Connect (OSTI)

A new decontamination method has been investigated and used during two demonstration stages by the Clean-Up Business Unit of AREVA. This new method is based on the use of a Laser beam to remove the contaminants present on a base metal surface. In this paper will be presented the type of Laser used during those tests but also information regarding the efficiency obtained on non-contaminated (simulated contamination) and contaminated samples (from the CEA and La Hague facilities). Regarding the contaminated samples, in the first case, the contamination was a quite thick oxide layer. In the second case, most of the contamination was trapped in dust and thin grease layer. Some information such as scanning electron microscopy (SEM), X-Ray scattering spectroscopy and decontamination factors (DF) will be provided in this paper. Laser technology appears to be an interesting one for the future of the D and D applications. As shown in this paper, the results in terms of efficiency are really promising and in many cases, higher than those obtained with conventional techniques. One of the most important advantages is that all those results have been obtained with no generation of secondary wastes such as abrasives, chemicals, or disks... Moreover, as mentioned in introduction, the Laser ablation process can be defined as a 'dry' process. This technology does not produce any liquid waste (as it can be the case with chemical process or HP water process...). Finally, the addition of a vacuum system allows to trap the contamination onto filters and thus avoiding any dissemination in the room where the process takes place. The next step is going to be a commercial use in 2012 in one of the La Hague buildings. (authors)

Moggia, Fabrice; Lecardonnel, Xavier; Damerval, Frederique [AREVA, Back End Business Group, Clean Up Business Unit (France)

2012-07-01T23:59:59.000Z

23

Laser ablation for the synthesis of carbon nanotubes  

SciTech Connect (OSTI)

Single walled carbon nanotubes are produced in a novel apparatus by the laser-induced ablation of moving carbon target. The laser used is of high average power and ultra-fast pulsing. According to various preferred embodiments, the laser produces and output above about 50 watts/cm.sup.2 at a repetition rate above about 15 MHz and exhibits a pulse duration below about 10 picoseconds. The carbon, carbon/catalyst target and the laser beam are moved relative to one another and a focused flow of "side pumped", preheated inert gas is introduced near the point of ablation to minimize or eliminate interference by the ablated plume by removal of the plume and introduction of new target area for incidence with the laser beam. When the target is moved relative to the laser beam, rotational or translational movement may be imparted thereto, but rotation of the target is preferred.

Holloway, Brian C; Eklund, Peter C; Smith, Michael W; Jordan, Kevin C; Shinn, Michelle

2012-11-27T23:59:59.000Z

24

E-Print Network 3.0 - arf laser ablation Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

laser ablation Search Powered by Explorit Topic List Advanced Search Sample search results for: arf laser ablation Page: << < 1 2 3 4 5 > >> 1 Lasers in Surgery and Medicine...

25

Laser ablation of nanoscale particles with 193 nm light  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Laser ablation of nanoscale particles with 193 nm light Laser ablation of nanoscale particles with 193 nm light Title Laser ablation of nanoscale particles with 193 nm light Publication Type Journal Article Year of Publication 2007 Authors Choi, Jong Hyun, Donald Lucas, and Catherine P. Koshland Journal Journal of Physics: Conference Series Volume 59 Start Page 54 Issue 1 Pagination 54-59 Abstract Laser interaction with nanoscale particles is distinct and different from laser-bulk material interaction, where a hot plasma is normally created. Here, we review our studies on 193 nm laser ablation of various nanoscale particles including NaCl, soot, polystyrene, and gold. The 20 ns laser beam with fluences up to 0.3 J/cm2 irradiates nanoparticles in a gas stream at laser repetition rates from 10 to 100 Hz. The particle size distributions before and after irradiation are measured with a scanning mobility particle sizer (SMPS), and particle morphology is examined with electron microscopy. All the nanomaterials studied exhibit a similar disintegration pattern and similar particle formation characteristics. No broadband emission associated with particle heating or optical breakdown is observed. The nanoparticles formed after irradiation have a smaller mean diameter and an order of magnitude higher number concentration with a more spherical shape compared to the original particles. We use the photon-atom ratio (PAR) to interpret the laser-particle interaction energetics.

26

Laser ablation ignition of premixed methane and oxygen-enriched air mixtures using a tantalum target  

Science Journals Connector (OSTI)

We report the laser ablation ignition of premixed methane and oxygen-enriched air mixtures using a tantalum target. The minimum laser pulse energy (MPE) of the ablation ignition was...

Li, Xiaohui; Yu, Xin; Fan, Rongwei; Yu, Yang; Liu, Chang; Chen, Deying

2014-01-01T23:59:59.000Z

27

Nanoscale patterning of graphene through femtosecond laser ablation  

SciTech Connect (OSTI)

We report on nanometer-scale patterning of single layer graphene on SiO{sub 2}/Si substrate through femtosecond laser ablation. The pulse fluence is adjusted around the single-pulse ablation threshold of graphene. It is shown that, even though both SiO{sub 2} and Si have more absorption in the linear regime compared to graphene, the substrate can be kept intact during the process. This is achieved by scanning the sample under laser illumination at speeds yielding a few numbers of overlapping pulses at a certain point, thereby effectively shielding the substrate. By adjusting laser fluence and translation speed, 400?nm wide ablation channels could be achieved over 100??m length. Raster scanning of the sample yields well-ordered periodic structures, provided that sufficient gap is left between channels. Nanoscale patterning of graphene without substrate damage is verified with Scanning Electron Microscope and Raman studies.

Sahin, R.; Akturk, S., E-mail: selcuk.akturk@itu.edu.tr [Department of Physics, Istanbul Technical University, Maslak 34469, Istanbul (Turkey); Simsek, E. [Electrical and Computer Engineering, The George Washington University, Washington, DC 20052 (United States)

2014-02-03T23:59:59.000Z

28

Surface instability on a metal target from multi-pulse KrF laser ablation  

SciTech Connect (OSTI)

Aluminum targets were ablated by focusing a KrF excimer laser down to a spot size of 0.05 cm{sup 2} with a fluence of approximately 4.9 J/cm{sup 2}. After a few tens of pulses, surface irregularities (corrugations and pits) progressively emerge, with size 1--100 {micro}m which is much larger than the laser wavelength. After hundreds of laser pulses, large scale wavelike patterns, on the order of 20 {micro}m, are observed on the aluminum surface. The authors propose that these wave patterns are caused by the Kelvin-Helmholtz instability at the interface of the molten aluminum and the plasma plume. A parametric study is given in terms of the molten layer`s thickness and of the spatial extent and kinetic energy density in the laser-produced plasma plume. Also included is an estimate of the cumulative growth in a multi-pulse laser ablation experiment. These estimates indicate that the Kelvin-Helmholtz instability is a viable mechanism for the formation of the large scale structures. Once formed, these large scale surface roughness causes multiple reflections of the laser light, and may increase the absorption coefficient over a pristine, flat surface by an order of magnitude.

Ang, L.K.; Lau, Y.Y.; Gilgenbach, R.M.; Kovaleski, S.D. [Univ. of Michigan, Ann Arbor, MI (United States); Spindler, H.L. [Boeing Corp., Seattle, WA (United States); Lash, J.S. [Sandia National Lab., Albuquerque, NM (United States)

1998-12-31T23:59:59.000Z

29

Femtosecond Laser Ablation: Fundamentals and Applications  

E-Print Network [OSTI]

. Freeman Á P. K. Diwakar Á A. Hassanein Center for Materials Under Extreme Environment, School of Nuclear- switched lasers, and subsequent light emission is collected and dispersed using a spectrograph

Harilal, S. S.

30

Pre-ignition laser ablation of nanocomposite energetic materials  

SciTech Connect (OSTI)

Laser ignition of energetic material composites was studied for initiation with heating rates from 9.5 Multiplication-Sign 10{sup 4} to 1.7 Multiplication-Sign 10{sup 7} K/s. This is a unique heating rate regime for laser ignition studies because most studies employ either continuous wave CO{sub 2} lasers to provide thermal ignition or pulsed Nd:YAG lasers to provide shock ignition. In this study, aluminum (Al) and molybdenum trioxide (MoO{sub 3}) nanoparticle powders were pressed into consolidated pellets and ignited using a Nd:YAG laser (1064 nm wavelength) with varied pulse energy. Results show reduced ignition delay times corresponding to laser powers at the ablation threshold for the sample. Heating rate and absorption coefficient were determined from an axisymmetric heat transfer model. The model estimates absorption coefficients from 0.1 to 0.15 for consolidated pellets of Al + MoO{sub 3} at 1064 nm wavelength. Ablation resulted from fracturing caused by a rapid increase in thermal stress and slowed ignition of the pellet.

Stacy, S. C.; Massad, R. A.; Pantoya, M. L. [Department of Mechanical Engineering, Texas Tech University, Lubbock, Texas 79409 (United States)] [Department of Mechanical Engineering, Texas Tech University, Lubbock, Texas 79409 (United States)

2013-06-07T23:59:59.000Z

31

Laser ablation electrospray ionization (LAESI) for atmospheric pressure, In vivo, and imaging mass spectrometry  

DOE Patents [OSTI]

The field of the invention is atmospheric pressure mass spectrometry (MS), and more specifically a process and apparatus which combine infrared laser ablation (LA) with electrospray ionization (ESI).

Vertes, Akos (Reston, VA); Nemes, Peter (Silver Spring, MD)

2011-11-29T23:59:59.000Z

32

Laser ablation electrospray ionization (LAESI) for atmospheric pressure, in vivo, and imaging mass spectrometry  

DOE Patents [OSTI]

The field of the invention is atmospheric pressure mass spectrometry (MS), and more specifically a process and apparatus which combine infrared laser ablation with electrospray ionization (ESI).

Vertes, Akos; Nemes, Peter

2014-08-19T23:59:59.000Z

33

E-Print Network 3.0 - ablative fractional lasers Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

www.sciencedirect.com SiliconPV: 17-20 April 2011, Freiburg, Germany Summary: selective laser ablation for local contacts to thin emitters Felix Haasea *, Enrique Garralaga...

34

Laser ablation electrospray ionization (LAESI) for atmospheric pressure, in vivo, and imaging mass spectrometry  

DOE Patents [OSTI]

The field of the invention is atmospheric pressure mass spectrometry (MS), and more specifically a process and apparatus which combine infrared laser ablation with electrospray ionization (ESI).

Vertes, Akos; Nemes, Peter

2013-07-16T23:59:59.000Z

35

Three-dimensional molecular imaging by infrared laser ablation electrospray ionization mass spectrometry  

DOE Patents [OSTI]

The field of the invention is atmospheric pressure mass spectrometry (MS), and more specifically a process and apparatus which combine infrared laser ablation with electrospray ionization (ESI).

Vertes, Akos; Nemes, Peter

2013-07-16T23:59:59.000Z

36

Three-dimensional molecular imaging by infrared laser ablation electrospray ionization mass spectrometry  

DOE Patents [OSTI]

The field of the invention is atmospheric pressure mass spectrometry (MS), and more specifically a process and apparatus which combine infrared laser ablation with electrospray ionization (ESI).

Vertes, Akos; Nemes, Peter

2012-10-30T23:59:59.000Z

37

Femtosecond-laser induced ablation of silicate glasses and the intrinsic dissociation energy  

Science Journals Connector (OSTI)

The relation between ablation threshold fluence upon femtosecond laser pulse irradiation and the average dissociation energy density of silicate based multicomponent glass is studied....

Grehn, Moritz; Seuthe, Thomas; Hfner, Michael; Griga, Nils; Theiss, Christoph; Mermillod-Blondin, Alexandre; Eberstein, Markus; Eichler, Hans; Bonse, Jrn

2014-01-01T23:59:59.000Z

38

Testing of concrete by laser ablation  

DOE Patents [OSTI]

A method is disclosed for testing concrete in a structure in situ, by: directing a succession of pulses of laser radiation at a point on the structure so that each pulse effects removal of a quantity of concrete and transfers energy to the concrete; detecting a characteristic of energy which has been transferred to the concrete; determining, separately from the detecting step, the total quantity of concrete removed by the succession of pulses; and calculating a property of the concrete on the basis of the detected energy characteristic and the determined total quantity of concrete removed. 1 fig.

Flesher, D.J.; Becker, D.L.; Beem, W.L.; Berry, T.C.; Cannon, N.S.

1997-01-07T23:59:59.000Z

39

Laser ablative synthesis of carbon nanotubes  

DOE Patents [OSTI]

An improved method for the production of single walled carbon nanotubes that utilizes an RF-induction heated side-pumped synthesis chamber for the production of such. Such a method, while capable of producing large volumes of carbon nanotubes, concurrently permits the use of a simplified apparatus that allows for greatly reduced heat up and cool down times and flexible flowpaths that can be readily modified for production efficiency optimization. The method of the present invention utilizes a free electron laser operating at high average and peak fluence to illuminate a rotating and translating graphite/catalyst target to obtain high yields of SWNTs without the use of a vacuum chamber.

Smith, Michael W. (Newport News, VA); Jordan, Kevin (Newport News, VA); Park, Cheol (Yorktown, VA)

2010-03-02T23:59:59.000Z

40

Testing of concrete by laser ablation  

DOE Patents [OSTI]

A method of testing concrete in a structure in situ, by: directing a succession of pulses of laser radiation at a point on the structure so that each pulse effects removal of a quantity of concrete and transfers energy to the concrete; detecting a characteristic of energy which has been transferred to the concrete; determining, separately from the detecting step, the total quantity of concrete removed by the succession of pulses; and calculating a property of the concrete on the basis of the detected energy characteristic and the determined total quantity of concrete removed.

Flesher, Dann J. (Benton City, WA); Becker, David L. (Kennewick, WA); Beem, William L. (Kennewick, WA); Berry, Tommy C. (Kennewick, WA); Cannon, N. Scott (Kennewick, WA)

1997-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "kinetics laser ablation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

High-throughput metal nanoparticle catalysis by pulsed laser ablation Selim Senkan a,*, Michael Kahn a  

E-Print Network [OSTI]

High-throughput metal nanoparticle catalysis by pulsed laser ablation Selim Senkan a,*, Michael online 18 July 2006 Abstract A high-throughput pulsed laser ablation (HT-PLA) system was developed-TEM) and energy dispersive X-ray (EDX) spectroscopy, respectively. The supported nanoparticles created by HT

Senkan, Selim M.

42

Nanoscale patterning of graphene through femtosecond laser ablation R. Sahin, E. Simsek, and S. Akturk  

E-Print Network [OSTI]

Nanoscale patterning of graphene through femtosecond laser ablation R. Sahin, E. Simsek, and S.164.158.129 On: Mon, 10 Feb 2014 15:01:27 #12;Nanoscale patterning of graphene through femtosecond laser ablation 2014) We report on nanometer-scale patterning of single layer graphene on SiO2/Si substrate through

Simsek, Ergun

43

Process and structures for fabrication of solar cells with laser ablation steps to form contact holes  

DOE Patents [OSTI]

Contact holes of solar cells are formed by laser ablation to accomodate various solar cell designs. Use of a laser to form the contact holes is facilitated by replacing films formed on the diffusion regions with a film that has substantially uniform thickness. Contact holes may be formed to deep diffusion regions to increase the laser ablation process margins. The laser configuration may be tailored to form contact holes through dielectric films of varying thickness.

Harley, Gabriel; Smith, David D; Dennis, Tim; Waldhauer, Ann; Kim, Taeseok; Cousins, Peter John

2013-11-19T23:59:59.000Z

44

Laser ablation of silicate glasses doped with transuranic actinides  

SciTech Connect (OSTI)

Direct sampling laser ablation plasma mass spectrometry (DS-LAMS) was applied to silica glasses doped with {sup 237}Np, {sup 242}Pu or {sup 241}Am using a unique instrument recently installed into a transuranic glovebox. The primary goal was to assess the utility of mass spectrometry of directly ablated ions for facile evaluation of actinide (An) constituents of silicate glass immobilization matrices used for encapsulation of radionuclides. The instrument and general procedures have been described elsewhere. Three high-purity silicate glasses prepared by a sol-gel process (SG) and one conventional high-temperature (HT; melting point {approx} 1,450 C) borosilicate glass were studied. These glasses comprised the following constituents, with compositions expressed in mass percentages: Np-HT {approx} 30% SiO{sub 2} + 6% B{sub 2}O{sub 3} + 3% BaO + 13% Al{sub 2}O{sub 3} + 10% PbO + 30% La{sub 2}O{sub 3} + 8% {sup 237}NpO{sub 2}; Np-SG {approx} 70% SiO{sub 2} + 30% {sup 237}NpO{sub 2}; Pu-SG {approx} 70% SiO{sub 2} + 30% {sup 242}PuO{sub 2}; Am-SG {approx} 85% SiO{sub 2} + 15% {sup 241}AmO{sub 2}.

Gibson, J.K.; Haire, R.G.

1998-10-01T23:59:59.000Z

45

Ablation driven by hot electrons generated during the ignitor laser pulse in shock ignition  

SciTech Connect (OSTI)

An analytical model for the ablation driven by hot electrons is presented. The hot electrons are assumed to be generated during the high intensity laser spike used to produce the ignitor shock wave in the shock ignition driven inertial fusion concept, and to carry on the absorbed laser energy in its totality. Efficient energy coupling requires to keep the critical surface sufficiently close to the ablation front and this goal can be achieved for high laser intensities provided that the laser wavelength is short enough. Scaling laws for the ablation pressure and the other relevant magnitudes of the ablation cloud are found in terms of the laser and target parameters. The effect of the preformed plasma assembled by the compression pulse, previous to the ignitor, is also discussed. It is found that a minimum ratio between the compression and the ignitor pulses would be necessary for the adequate matching of the corresponding scale lengths.

Piriz, A. R.; Rodriguez Prieto, G. [E.T.S.I. Industriales, Universidad de Castilla-La Mancha and Instituto de Investigaciones Energeticas, 13071 Ciudad Real (Spain); Tahir, N. A. [GSI Helmholtzzentrum fuer Schwerionenforschung, Planckstrasse 1, 64291 Darmstadt (Germany); Zhang, Y. [School of Physics and Optoelectronic Technology, Dalian University of Technology, 116024 Dalian (China); Liu, S. D.; Zhao, Y. T. [Institute of Modern Physics, Chinese Academy of Science, 730000 Lanzhou (China)

2012-12-15T23:59:59.000Z

46

Laser ablation analysis of novel perfluoroalkyl-coated aluminum nanocomposites  

SciTech Connect (OSTI)

The evolution and decay of aluminum and aluminum monoxide emission signatures following a laser ablation event were used to compare the relative reaction rates of three aluminum based materials. Time-resolved emission results of oxide-free, C{sub 13}F{sub 27}CO{sub 2}H-passivated materials were compared with uncoated, oxide passivated aluminum nanoparticles and those coated with the same acid used in for passivation C{sub 13}F{sub 27}CO{sub 2}H. Excited state Al and AlO emission is reduced in time for the oxide free material when compared to coated, 50 nm, oxide passivated particles mixed on an equal active Al: C{sub 13}F{sub 27}CO{sub 2}H ratio. This is interpreted as an increase in the reaction rate afforded by the elimination of the oxide coating and proximity of oxidizing species in the SAM-based nanocomposite.

Jouet, R. Jason; Carney, Joel R.; Lightstone, James M.; Warren, Andrea D. [Research, Development, Test, and Evaluation, IHDIV, Naval Surface Warfare Center 4104 Evans Way, Suite 102 Indian Head MD 20640-5102 (United States)

2007-12-12T23:59:59.000Z

47

RAPID COMMUNICATION Quantifying the quality of femtosecond laser ablation of graphene  

E-Print Network [OSTI]

RAPID COMMUNICATION Quantifying the quality of femtosecond laser ablation of graphene Ramazan Sahin abla- tion quality and ablation size is experimentally studied on graphene-coated silicon Introduction Graphene micro- and nano-structures are considered potential building blocks for future opto

Simsek, Ergun

48

Infrared nanosecond laser-metal ablation in atmosphere: Initial plasma during laser pulse and further expansion  

SciTech Connect (OSTI)

We have investigated the dynamics of the nanosecond laser ablated plasma within and after the laser pulse irradiation using fast photography. A 1064 nm, 15 ns laser beam was focused onto a target made from various materials with an energy density in the order of J/mm{sup 2} in atmosphere. The plasma dynamics during the nanosecond laser pulse were observed, which could be divided into three stages: fast expansion, division into the primary plasma and the front plasma, and stagnation. After the laser terminated, a critical moment when the primary plasma expansion transited from the shock model to the drag model was resolved, and this phenomenon could be understood in terms of interactions between the primary and the front plasmas.

Wu, Jian; Wei, Wenfu; Li, Xingwen; Jia, Shenli; Qiu, Aici [State Key Laboratory of Electrical Insulation and Power Equipment, Xi'an Jiaotong University, Shaanxi 710049 (China)] [State Key Laboratory of Electrical Insulation and Power Equipment, Xi'an Jiaotong University, Shaanxi 710049 (China)

2013-04-22T23:59:59.000Z

49

Capabilities of Laser Ablation Mass Spectrometry in the Differentiation of Natural and Artificial Opal Gemstones  

Science Journals Connector (OSTI)

Si+,?K+,?Ca+, Zr+,?Hf+ ... The interaction of a laser beam with an inorganic compound leads different processes such as surface heating, phase change (fusion and vaporization of the target), ablation, and ionization20,21 to occur. ...

Eric Erel; Frdric Aubriet; Gisle Finqueneisel; Jean-Franois Muller

2003-10-22T23:59:59.000Z

50

Laser Ablation Inductively Coupled Plasma Mass Spectrometry Measurement of Isotope Ratios in Depleted Uranium Contaminated Soils  

Science Journals Connector (OSTI)

Laser ablation of pressed soil pellets was examined as a means of direct sample introduction to enable inductively coupled plasma mass spectrometry (ICP-MS) screening of soils for...

Seltzer, Michael D

2003-01-01T23:59:59.000Z

51

Glass particles produced by laser ablation for ICP-MS measurements  

E-Print Network [OSTI]

Glass particles produced by laser ablation for ICP-MS266nm) was used to generate glass particles from two sets ofWhen the current data on glass were compared with the metal

Gonzalez, J.; Liu, C.; Wen, S.; Mao, X.; Russo, R.E.

2008-01-01T23:59:59.000Z

52

Fundamentals of femtosecond laser ablation of dielectric materials  

SciTech Connect (OSTI)

The modeling of laser-excited dielectric materials requires a detailed description of the electronic excitation. Dielectric materials do not absorb visible light by traditional linear absorption, so the dynamical generation of conduction-band electrons strongly couples to the absorption. The generation of free electrons is initiated by strong-field excitation and followed by multiplication through impact ionization by energetic electrons heated by the laser. The present paper describes an approach to solving the coupled problem of electron excitation and one-dimensional light propagation. The electronic excitation is described in the so-called multiple-rate-equation model, and the light is absorbed by a combination of strong-field excitation and linear absorption by the excited electrons, which are assumed to behave as a free-electron gas described by a Drude model. The model is generic and based on a few key parameters: the wavelength and the pulse duration of the light, and the band gap of the dielectric medium. This allows parametric investigations of ablation phenomena.

Byskov-Nielsen, J.; Le, D. Q. S.; Christensen, M. N.; Balling, P. [Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C (Denmark); Christensen, B. H. [Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C (Denmark); Danish Technological Institute, Kongsvang Alle 29, 8000 Aarhus C (Denmark)

2010-10-08T23:59:59.000Z

53

Laser-based diagnostics for condensation in laser-ablated copper plasmas  

SciTech Connect (OSTI)

We are investigating the thermodynamic conditions under which condensation occurs in laser-ablated copper plasma plumes. The plasma is created by XeCl excimer laser ablation (308 nm, 350 mJ/pulse) at power densities from 500--1000 MW/cm{sup 2}. The atomic vapor expands rapidly into backing pressures of helium ranging from 0--50 torr. The backing gas serves to slow the vapor before it rarefies and provides a third body to stabilize collision complexes between vapor atoms to produce small cluster species. The formation of these small clusters is indicative of the onset of condensation, a process which, under the proper conditions, eventually forms macroscopic particulate in the plume. We use laser-induced fluorescence (LIF) to probe both atomic copper and the copper dimer molecule, Cu{sub 2}. Velocities of atomic Cu have been obtained by a time-of-flight method under varying conditions of backing gas pressure. At low pressure (10 mtorr), the atomic Cu velocity peaks at approximately 2 {times} 10{sup 6} cm/s. Excitation scans of the Cu{sub 2} A {minus} X (0,0) and (1,1) bands yield both a rotational temperature and a vibrational temperature. Direct laser beam absorption is used to determine the number density of atomic copper. Rayleigh scattering from particulate is easily observable under conditions favorable to particulate production. The Cu{sub 2} LIF and Rayleigh-scattered signals disappear instantaneously in the absence of the ablation laser pulse indicating that the particulate is formed during a single laser shot. 10 refs., 9 figs.

Sappey, A.D.; Gamble, T.K.

1991-01-01T23:59:59.000Z

54

Laser Ablation of Organic Materials for discrimination of bacteria in an  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Laser Ablation of Organic Materials for discrimination of bacteria in an Laser Ablation of Organic Materials for discrimination of bacteria in an organic background Title Laser Ablation of Organic Materials for discrimination of bacteria in an organic background Publication Type Conference Proceedings Year of Publication 2009 Authors Baudelet, Matthieu, Myriam Boueri, Jin Yu, Xianglei Mao, Samuel S. Mao, and Richard E. Russo Conference Name Ultrafast Phenomena in Semiconductors and Nanostructure Materials XIII Series Title Proceedings SPIE Volume 7214 Pagination 72140J Date Published 02/2009 Abstract We demonstrate in this paper that laser ablation allows efficient analysis of organic and biological materials. Such analysis is based on laser-induced breakdown spectroscopy (LIBS) which consists in the detection of the optical emission from the plasma induced by a high intensity laser pulse focused on the sample surface. The optimization of the ablation regime in terms of laser parameters (pulse duration, wavelength, fluence) is important to generate a plasma suitable for the analysis. We first present the results of a study of laser ablation of organic samples with different laser parameters using time-resolved shadowgraph. We correlate the early stage expansion of the plasma to its optical emission properties, which allows us to choose suitable laser parameters for an efficient analysis of organic or biological samples by LIBS. As an illustration of the analytical ability of LIBS for biological materials, we show that the emission from CN molecules can be used to distinguish between biological and inorganic samples. Native CN molecular fragment directly ablated from a biological sample are identified using time-resolved LIBS. Those due to recombination with nitrogen contained in atmospheric air can be distinguished with their specific time evolution behavior.

55

Fully Automated Laser Ablation Liquid Capture Sample Analysis using NanoElectrospray Ionization Mass Spectrometry  

SciTech Connect (OSTI)

RATIONALE: Laser ablation provides for the possibility of sampling a large variety of surfaces with high spatial resolution. This type of sampling when employed in conjunction with liquid capture followed by nanoelectrospray ionization provides the opportunity for sensitive and prolonged interrogation of samples by mass spectrometry as well as the ability to analyze surfaces not amenable to direct liquid extraction. METHODS: A fully automated, reflection geometry, laser ablation liquid capture spot sampling system was achieved by incorporating appropriate laser fiber optics and a focusing lens into a commercially available, liquid extraction surface analysis (LESA ) ready Advion TriVersa NanoMate system. RESULTS: Under optimized conditions about 10% of laser ablated material could be captured in a droplet positioned vertically over the ablation region using the NanoMate robot controlled pipette. The sampling spot size area with this laser ablation liquid capture surface analysis (LA/LCSA) mode of operation (typically about 120 m x 160 m) was approximately 50 times smaller than that achievable by direct liquid extraction using LESA (ca. 1 mm diameter liquid extraction spot). The set-up was successfully applied for the analysis of ink on glass and paper as well as the endogenous components in Alstroemeria Yellow King flower petals. In a second mode of operation with a comparable sampling spot size, termed laser ablation/LESA , the laser system was used to drill through, penetrate, or otherwise expose material beneath a solvent resistant surface. Once drilled, LESA was effective in sampling soluble material exposed at that location on the surface. CONCLUSIONS: Incorporating the capability for different laser ablation liquid capture spot sampling modes of operation into a LESA ready Advion TriVersa NanoMate enhanced the spot sampling spatial resolution of this device and broadened the surface types amenable to analysis to include absorbent and solvent resistant materials.

Lorenz, Matthias [ORNL] [ORNL; Ovchinnikova, Olga S [ORNL] [ORNL; Van Berkel, Gary J [ORNL] [ORNL

2014-01-01T23:59:59.000Z

56

Toward laser ablation Accelerator Mass Spectrometry of actinides  

SciTech Connect (OSTI)

A project to measure neutron capture cross sections of a number of actinides in a reactor environment by Accelerator Mass Spectrometry (AMS) at the ATLAS facility of Argonne National Laboratory is underway. This project will require the precise and accurate measurement of produced actinide isotopes in many (>30) samples irradiated in the Advanced Test Reactor at Idaho National Laboratory with neutron fluxes having different energy distributions. The AMS technique at ATLAS is based on production of highlycharged positive ions in an electron cyclotron resonance (ECR) ion source followed by acceleration in the ATLAS linac and mass-to-charge (m/q) measurement at the focus of the Fragment Mass Analyzer. Laser ablation was selected as the method of feeding the actinide material into the ion source because we expect it will have higher efficiency and lower chamber contamination than either the oven or sputtering techniques, because of a much narrower angular distribution of emitted material. In addition, a new multi-sample holder/changer to allow quick change between samples and a computer-controlled routine allowing fast tuning of the accelerator for different beams, are being developed. An initial test run studying backgrounds, detector response, and accelerator scaling repeatability was conducted in December 2010. The project design, schedule, and results of the initial test run to study backgrounds are discussed.

R. C. Pardo; F. G. Kondev; S. Kondrashev; C. Nair; T. Palchan; R. Scott; D. Seweryniak; R. Vondrasek; M. Paul; P. Collon; C. Deibel; M. Salvatores; G. Palmiotti; J. Berg; J. Fonnesbeck; G. Imel

2013-01-01T23:59:59.000Z

57

Nanoparticle generation and transport resulting from femtosecond laser ablation of ultrathin metal films: Time-resolved measurements and molecular dynamics  

E-Print Network [OSTI]

Nanoparticle generation and transport resulting from femtosecond laser ablation of ultrathin metal and redeposited nanoparticles J. Appl. Phys. 115, 124302 (2014); 10.1063/1.4869456 Impact of wavelength dependent thermo-elastic laser ablation mechanism on the generation of nanoparticles from thin gold films Appl

Geohegan, David B.

58

New Combined Laser Ablation Platform Determines Cell Wall Chemistry (Fact Sheet)  

SciTech Connect (OSTI)

NREL has designed and developed a combined laser ablation/pulsed sample introduction/mass spectrometry platform that integrates pyrolysis and/or laser ablation with resonance-enhanced multiphoton ionization (REMPI) time-of-flight mass spectrometry. Using this apparatus, we can measure the cell wall chemical composition of untreated biomass materials. Understanding the chemical composition of untreated biomass is key to both the biochemical and thermochemical conversion of lignocellulosic biomass to biofuels. In the biochemical conversion process, the new technique provides a better understanding of the chemistry of lignin and will improve accessibility to plant sugars. In thermochemical conversion, the information provided by the new technique may help to reduce the formation of unwanted byproducts during gasification. NREL validated the ability of the system to detect pyrolysis products from plant materials using poplar, a potentially high-impact bioenergy feedstock. In the technique, biomass vapors are produced by laser ablation using the 3rd harmonic of an Nd:YAG laser (355 nm). The resulting vapors are entrained in a free jet expansion of helium, then skimmed and introduced into an ionization region. REMPI is used to ionize the vapors because it is highly sensitive for detecting lignin and aromatic metabolites. The laser ablation method was used to selectively volatilize specific plant tissues and detect lignin-based products from the vapors with enhanced sensitivity. This will allow the determination of lignin distribution in future biomass studies.

Not Available

2011-09-01T23:59:59.000Z

59

Kinetic modelling of krypton fluoride laser systems  

SciTech Connect (OSTI)

A kinetic model has been developed for the KrF* rare gas halide laser system, specifically for electron-beam pumped mixtures of krypton, fluorine, and either helium or argon. The excitation produced in the laser gas by the e-beam was calculated numerically using an algorithm checked by comparing the predicted ionization yields in the pure rare gases with their experimental values. The excitation of the laser media by multi-kilovolt x-rays was also modeled and shown to be similar to that produced by high energy electrons. A system of equations describing the transfer of the initial gas excitation into the laser upper level was assembled using reaction rate constants from both experiment and theory. A one-dimensional treatment of the interaction of the laser radiation with the gas was formulated which considered spontaneous and stimulated emission and absorption. The predictions of this model were in good agreement with the fluorescence signals and gain and absorption measured experimentally.

Jancaitis, K.S.

1983-11-01T23:59:59.000Z

60

Single-shot and single-spot measurement of laser ablation threshold for carbon nanotubes  

E-Print Network [OSTI]

A simple and convenient procedure for single-shot, single-spot ablation threshold measurement has been developed. It is based on the employment of cylindrical lens to obtain elliptical Gaussian laser spot. The ablated spot chords which are parallel to the minor axis were measured across the spot major axis which is proportional to the fluence cross-section thus providing wide range dependence of damaged spot size versus fluence in one spot measurement. For both conventional and new-developed procedures the ablation threshold for typical Nd:YAG laser parameters (1064 nm, 10 ns) has been measured as 50 mJ/cm2 which is one order of magnitude lower than that for a bulk graphite.

Lednev, Vasily N; Obraztsova, Elena D; Kudryashov, Sergey I; Bunkin, Alexey F

2013-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "kinetics laser ablation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

Investigation of the effect of water content, thickness and optical properties on laser ablation of biological tissue  

E-Print Network [OSTI]

. Polyacrylamide gel was used as an experimental model for biological tissue in the thickness experiments using the Er:YAG laser. The mass of the gel was measured before and after ablation. The front diameter of ablation was also monitored. The ablation rate... was studied as a function of gel position. By moving the polyacrylamide gel away from the biconvex lens, the beam diameter of the Er:YAG laser was increased. The ablation rate decreased almost exponentially with increasing beam diameter as did the energy...

Vaidyanathan, Varadarajan

1991-01-01T23:59:59.000Z

62

Plasma analyses during femtosecond laser ablation of Ti, Zr, and Hf  

SciTech Connect (OSTI)

Femtosecond laser ablation of Ti, Zr, and Hf has been investigated by means of in situ plasma diagnostics. Fast imaging was used to characterize the plasma plume expansion on a nanosecond time scale. In addition, time- and space-resolved optical emission spectroscopy was employed to determine the plume composition and the characteristic expansion velocities of plasma species. It is shown that two plume components with different expansion velocities are generated by the interaction of ultrashort laser pulses with metals. The composition and the expansion behavior of the two components have been analyzed as a function of laser fluence and target material. The results are discussed in terms of mechanisms responsible for ablation by ultrashort laser pulses.

Grojo, D.; Hermann, J.; Perrone, A. [LP3-UMR 6182 Centre National de la Recherche Scientifique, Faculte des Sciences de Luminy, Case 917, 13288 Marseille Cedex 9 (France); University of Lecce, Physics Department and National Nanotechnology Laboratory, 73100-Lecce (Italy)

2005-03-15T23:59:59.000Z

63

Experimental scaling law for mass ablation rate from a Sn plasma generated by a 1064 nm laser  

E-Print Network [OSTI]

. INTRODUCTION Laser produced Sn plasma, in its role as an efficient extreme ultraviolet EUV x-ray sourceExperimental scaling law for mass ablation rate from a Sn plasma generated by a 1064 nm laser depth in planar Sn targets irradiated with a pulsed 1064 nm laser was investigated over laser

Najmabadi, Farrokh

64

Multiscale simulation of laser ablation of organic solids: evolution of the plume  

E-Print Network [OSTI]

with appropriate resolutions and, at the same time, accounts for the interrelations among the processes at different time- and length-scales are strongly coupled and interrelated. On the microscale, the processes. The combined multiscale model addresses different processes involved in the laser ablation phenomenon

Zhigilei, Leonid V.

65

Inductively Coupled Plasma: Fundamental Particle Investigations with Laser Ablation and Applications in Magnetic Sector Mass Spectrometry  

SciTech Connect (OSTI)

Particle size effects and elemental fractionation in laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) are investigated with nanosecond and femtosecond laser ablation, differential mobility analysis, and magnetic sector ICP-MS. Laser pulse width was found to have a significant influence on the LA particle size distribution and the elemental composition of the aerosol and thus fractionation. Emission from individual particles from solution nebulization, glass, and a pressed powder pellet are observed with high speed digital photography. The presence of intact particles in an ICP is shown to be a likely source of fractionation. A technique for the online detection of stimulated elemental release from neural tissue using magnetic sector ICP-MS is described. Detection limits of 1 {micro}g L{sup -1} or better were found for P, Mn, Fe, Cu, and Zn in a 60 {micro}L injection in a physiological saline matrix.

Nathan Joe Saetveit

2008-08-18T23:59:59.000Z

66

Two-dimensional space-resolved emission spectroscopy of laser ablation plasma in water  

SciTech Connect (OSTI)

We developed a method for two-dimensional space-resolved emission spectroscopy of laser-induced plasma in water to investigate the spatial distribution of atomic species involved in the plasma. Using this method, the laser ablation plasma produced on a Cu target in 5 mM NaCl aqueous solution was examined. The emission spectrum varied considerably depending on the detecting position. The temperature and the atomic density ratio N{sub Na}/N{sub Cu} at various detecting positions were evaluated by fitting emission spectra to a theoretical model based on the Boltzmann distribution. We are successful in observing even a small difference between the distributions of the plasma parameters along the directions vertical and horizontal to the surface. The present approach gives direct information for sound understanding of the behavior of laser ablation plasma produced on a solid surface in water.

Matsumoto, Ayumu; Tamura, Ayaka; Fukami, Kazuhiro; Ogata, Yukio H. [Institute of Advanced Energy, Kyoto University, Uji, Kyoto 611-0011 (Japan); Sakka, Tetsuo [Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Kyoto 615-8510 (Japan)

2013-02-07T23:59:59.000Z

67

Titanium nitride thin films deposited by reactive pulsed-laser ablation in RF plasma  

Science Journals Connector (OSTI)

Titanium nitride thin films were deposited on Si (100) substrates by pulsed laser ablation of a titanium target in a N2 atmosphere (gas pressure approx. 10 Pa) using a doubled frequency Nd:YAG laser (532 nm) also assisted by a 13.56-MHz radio frequency (RF) plasma. Deposition was carried out at various substrate temperatures ranging from 373 up to 873 K and films were analyzed by X-ray diffractometry, scanning electron microscopy and optical emission spectroscopy. A comparison between the normal pulsed laser deposition (PLD) and the RF plasma-assisted PLD showed the influence of the plasma on the structural characteristics of the thin films.

A. Giardini; V. Marotta; S. Orlando; G.P. Parisi

2002-01-01T23:59:59.000Z

68

Broadening of the spectral lines of a buffer gas and target substance in laser ablation  

SciTech Connect (OSTI)

The broadening of discrete spectral lines from the plasma produced in the laser ablation of metal targets in a broad pressure range (10{sup 2} - 10{sup 7} Pa) of the ambient gas (Ar, He, H{sub 2}) was studied experimentally. The behaviour of spectral line broadening for the buffer gases was found to be significantly different from that for the atoms and ions of the target material. In comparison with target atoms, the atoms of buffer gases radiate from denser plasma layers, and their spectral line profiles are complex in shape. (interaction of laser radiation with matter. laser plasma)

Kask, Nikolai E; Michurin, Sergei V [D.V. Skobel'tsyn Institute of Nuclear Physics, M.V. Lomonosov Moscow State University, Moscow (Russian Federation)

2012-11-30T23:59:59.000Z

69

Safeguards Verification Measurements using Laser Ablation, Absorbance Ratio Spectrometry in Gaseous Centrifuge Enrichment Plants  

SciTech Connect (OSTI)

Laser Ablation Absorbance Ratio Spectrometry (LAARS) is a new verification measurement technology under development at the US Department of Energy (DOE) Pacific Northwest National Laboratory (PNNL). LAARS uses three lasers to ablate and then measure the relative isotopic abundance of uranium compounds. An ablation laser is tightly focused on uranium-bearing solids, producing a small atomic uranium vapor plume. Two collinear wavelength-tuned spectrometry lasers transit through the plume and the absorbance of U-235 and U-238 isotopes are measured to determine U-235 enrichment. The measurement is independent of chemical form and degree of dilution with nuisance dust and other materials. LAARS has high relative precision and detection limits approaching the femtogram range for U-235. The sample is scanned and assayed point-by-point at rates reaching 1 million measurements/hour, enabling LAARS to detect and analyze uranium in trace samples. The spectrometer is assembled using primarily commercially available components and features a compact design and automated analysis.Two specific gaseous centrifuge enrichment plant (GCEP) applications of the spectrometer are currently under development: 1) LAARS-Environmental Sampling (ES), which collects and analyzes aerosol particles for GCEP misuse detection and 2) LAARS-Destructive Assay (DA), which enables onsite enrichment DA sample collection and analysis for protracted diversion detection. The two applications propose game-changing technological advances in GCEP safeguards verification.

Anheier, Norman C.; Cannon, Bret D.; Kulkarni, Gourihar R.; Munley, John T.; Nelson, Danny A.; Qiao, Hong (Amy) [Amy; Phillips, Jon R.

2012-07-17T23:59:59.000Z

70

Ultraviolet versus infrared: Effects of ablation laser wavelength on the expansion of laser-induced plasma into one-atmosphere argon gas  

SciTech Connect (OSTI)

Laser-induced plasma from an aluminum target in one-atmosphere argon background has been investigated with ablation using nanosecond ultraviolet (UV: 355 nm) or infrared (IR: 1064 nm) laser pulses. Time- and space-resolved emission spectroscopy was used as a diagnostics tool to have access to the plasma parameters during its propagation into the background, such as optical emission intensity, electron density, and temperature. The specific feature of nanosecond laser ablation is that the pulse duration is significantly longer than the initiation time of the plasma. Laser-supported absorption wave due to post-ablation absorption of the laser radiation by the vapor plume and the shocked background gas plays a dominant role in the propagation and subsequently the behavior of the plasma. We demonstrate that the difference in absorption rate between UV and IR radiations leads to different propagation behaviors of the plasma produced with these radiations. The consequence is that higher electron density and temperature are observed for UV ablation. While for IR ablation, the plasma is found with lower electron density and temperature in a larger and more homogenous axial profile. The difference is also that for UV ablation, the background gas is principally evacuated by the expansion of the vapor plume as predicted by the standard piston model. While for IR ablation, the background gas is effectively mixed to the ejected vapor at least hundreds of nanoseconds after the initiation of the plasma. Our observations suggest a description by laser-supported combustion wave for the propagation of the plasma produced by UV laser, while that by laser-supported detonation wave for the propagation of the plasma produced by IR laser. Finally, practical consequences of specific expansion behavior for UV or IR ablation are discussed in terms of analytical performance promised by corresponding plasmas for application with laser-induced breakdown spectroscopy.

Ma Qianli; Motto-Ros, Vincent; Laye, Fabrice; Yu Jin [Universite de Lyon, F-69622, Lyon, France, Universite Lyon 1, Villeurbanne, CNRS, UMR5579, LASIM (France); Lei Wenqi; Bai Xueshi; Zheng Lijuan; Zeng Heping [State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai (China)

2012-03-01T23:59:59.000Z

71

Surface chemical reaction of laser ablated aluminum sample for detonation initiation  

SciTech Connect (OSTI)

We explore the evolution of metal plasma generated by high laser irradiances and its effect on the surrounding air by using shadowgraph images after laser pulse termination; hence the formation of laser supported detonation and combustion processes has been investigated. The essence of the paper is in observing initiation of chemical reaction between ablated aluminum plasma and oxygen from air by inducing high power laser pulse (>1000 mJ/pulse) and conduct a quantitative comparison of chemically reactive laser initiated waves with the classical detonation of exploding aluminum (dust) cloud in air. Findings in this work may lead to a new method of initiating detonation from metal sample in its bulk form without the need of mixing nano-particles with oxygen for initiation.

Kim, Chang-hwan; Yoh, Jack J. [School of Mechanical and Aerospace Engineering, Seoul National University, 599 Kwanakro, Kwanakgu, Seoul, Korea 151-742 (Korea, Republic of)

2011-05-01T23:59:59.000Z

72

Picosecond laser ablation of nano-sized WTi thin film  

Science Journals Connector (OSTI)

Interaction of an Nd:YAG laser, operating at 532 nm wavelength and pulse duration of 40 ps, with tungsten-titanium (WTi) thin film (thickness, 190 nm)...2...were found to be sufficient for modification of the WTi

S. Petrovi?; B. Gakovi?; D. Peruko; T. Desai; D. Batani; M. ?ekada

2009-08-01T23:59:59.000Z

73

Generation of low work function, stable compound thin films by laser ablation  

DOE Patents [OSTI]

Generation of low work function, stable compound thin films by laser ablation. Compound thin films with low work function can be synthesized by simultaneously laser ablating silicon, for example, and thermal evaporating an alkali metal into an oxygen environment. For example, the compound thin film may be composed of Si/Cs/O. The work functions of the thin films can be varied by changing the silicon/alkali metal/oxygen ratio. Low work functions of the compound thin films deposited on silicon substrates were confirmed by ultraviolet photoelectron spectroscopy (UPS). The compound thin films are stable up to 500.degree. C. as measured by x-ray photoelectron spectroscopy (XPS). Tests have established that for certain chemical compositions and annealing temperatures of the compound thin films, negative electron affinity (NEA) was detected. The low work function, stable compound thin films can be utilized in solar cells, field emission flat panel displays, electron guns, and cold cathode electron guns.

Dinh, Long N. (Concord, CA); McLean, II, William (Oakland, CA); Balooch, Mehdi (Berkeley, CA); Fehring, Jr., Edward J. (Dublin, CA); Schildbach, Marcus A. (Livermore, CA)

2001-01-01T23:59:59.000Z

74

Optical time of flight studies of lithium plasma in double pulse laser ablation: Evidence of inverse Bremsstrahlung absorption  

SciTech Connect (OSTI)

The early stage of formation of lithium plasma in a collineardouble pulse laser ablation mode has been studied using optical time of flight (OTOF) spectroscopy as a function of inter-pulse delay time, the distance from the target surface and the fluence of the ablation lasers. The experimental TOF measurements were carried out for lithium neutral (670.8?nm and 610.3?nm), and ionic (548.4?nm and 478.8?nm) lines. These experimental observations have been compared with that for single pulse laser ablation mode. It is found that depending on the fluence and laser pulse shape of the first pre-ablation laser and the second main ablation laser, the plasma plume formation and its characteristic features can be described in terms of plume-plume or laser-plume interaction processes. Moreover, the enhancement in the intensity of Li neutral and ionic lines is observed when the laser-plume interaction is the dominant process. Here, we see the evidence of the role of inverse Bremsstrahlung absorption process in the initial stage of formation of lithium plasma in this case.

Sivakumaran, V.; Joshi, H. C.; Singh, R. K.; Kumar, Ajai, E-mail: ajai@ipr.res.in [Institute for Plasma Research, Bhat, Gandhinagar, Gujarat 382428 (India)

2014-06-15T23:59:59.000Z

75

Laser Ablation Molecular Isotopic Spectrometry: Parameter influence on boron isotope measurements  

Science Journals Connector (OSTI)

Laser Ablation Molecular Isotopic Spectrometry (LAMIS) was recently reported for optical isotopic analysis of condensed samples in ambient air and at ambient pressure. LAMIS utilizes molecular emissions which exhibit larger isotopic spectral shits than in atomic transitions. For boron monoxide 10BO and 11BO, the isotopic shifts extend from 114cm?1 (0.74nm) to 145238cm?1 (58nm) at the B 2?+ (v=0)?X 2?+ (v=2) and A 2?i (v=0)?X 2?+ (v=3) transitions, respectively. These molecular isotopic shifts are over two orders of magnitude larger than the maximum isotopic shift of approximately 0.6cm?1 in atomic boron. This paper describes how boron isotope abundance can be quantitatively determined using LAMIS and how atomic, ionic, and molecular optical emission develops in a plasma emanating from laser ablation of solid samples with various boron isotopic composition. We demonstrate that requirements for spectral resolution of the measurement system can be significantly relaxed when the isotopic abundance ratio is determined using chemometric analysis of spectra. Sensitivity can be improved by using a second slightly delayed laser pulse arriving into an expanding plume created by the first ablation pulse.

Xianglei Mao; Alexander A. Bol'shakov; Dale L. Perry; Osman Sorkhabi; Richard E. Russo

2011-01-01T23:59:59.000Z

76

Laser ablation of contaminants from concrete and metal surfaces. Topical report, June--December 1994  

SciTech Connect (OSTI)

Tests have demonstrated that it is possible to clean coatings off surfaces using high-power, pulsed, high-repetition-rate lasers. Purpose of this contract is to demonstrate (1) that pulsed-repetition lasers can be used to remove paint from concrete and metal surfaces, including cleaning out the surface pores, (2) that the cleaning process will result in negligible release of contaminated ablated material to the environment, and (3) that the process generates negligible additional waste compared to competing technologies. This report covers technical progress during Phase 1 of the contract and makes recommendations for technology development in Phase 2.

Freiwald, J.; Freiwald, D.A.

1994-12-01T23:59:59.000Z

77

Ignition characteristics of laser-ablated aluminum at shock pressures up to 2?GPa  

SciTech Connect (OSTI)

The ignition of aluminum particles under high pressure and temperature conditions is considered. The laser ablation method is used to generate oxide-free aluminum particles exposed to pressures ranging between 0.35 and 2.2?GPa. A continuous wave CO{sub 2} laser radiation heats the surface of the aluminum target until ignition is observed. We confirm ignition by a spectroscopic analysis of AlO vibronic band of 484?nm wavelength, and the radiant temperature is measured with respect to various pressures for estimating the heating energy for ignition. The ignition characteristics of the oxide-free aluminum particles exposed to extremely high pressures are reported.

Lee, Kyung-Cheol; Young Lee, Jae; Yoh, Jack J., E-mail: jjyoh@snu.ac.kr [Department of Mechanical and Aerospace Engineering, Seoul National University, 1 Gwanakro, Gwanakgu, Seoul 151-742 (Korea, Republic of); Taira, Tsubasa [Division of Applied Physics, Hokkaido University, Sapporo (Japan); Mo Koo, Goon [Department of Aerospace Engineering, University of Maryland, College Park, Maryland 20742 (United States)

2014-01-07T23:59:59.000Z

78

Low work function surface layers produced by laser ablation using short-wavelength photons  

DOE Patents [OSTI]

Short-wavelength photons are used to ablate material from a low work function target onto a suitable substrate. The short-wavelength photons are at or below visible wavelength. The elemental composition of the deposit is controlled by the composition of the target and the gaseous environment in which the ablation process is performed. The process is carried out in a deposition chamber to which a short-wavelength laser is mounted and which includes a substrate holder which can be rotated, tilted, heated, or cooled. The target material is mounted onto a holder that spins the target during laser ablation. In addition, the deposition chamber is provided with a vacuum pump, an external gas supply with atomizer and radical generator, a gas generator for producing a flow of molecules on the substrate, and a substrate cleaning device, such as an ion gun. The substrate can be rotated and tilted, for example, whereby only the tip of an emitter can be coated with a low work function material.

Balooch, Mehdi (Berkeley, CA); Dinh, Long N. (Concord, CA); Siekhaus, Wigbert J. (Berkeley, CA)

2000-01-01T23:59:59.000Z

79

Nanoparticle generation and transport resulting from femtosecond laser ablation of ultrathin metal films: Time-resolved measurements  

E-Print Network [OSTI]

Nanoparticle generation and transport resulting from femtosecond laser ablation of ultrathin metal April 2014; published online 14 May 2014) The synthesis of metal nanoparticles by ultrafast laser nanoparticles with size distributions that were bimodal for the thicker films, but collapsed into a single mode

Zhigilei, Leonid V.

80

Toward Single-Cell Analysis by Plume Collimation in Laser Ablation Electrospray Ionization Mass Spectrometry  

Science Journals Connector (OSTI)

In the plume collimation experiments, laser radiation was delivered through a germanium oxide (GeO2) optical fiber (450 ?m core diameter, HP Fiber, Infrared Fiber Systems, Inc., Silver Spring, MD) with a tip etched in a 2% nitric acid solution as described earlier. ... Upon ablation in the capillary, a collimated plume emerges (shown in blue) and is ionized by an electrospray. ... Individual sea urchin eggs were selected by using the micromanipulator system and deposited into a capillary for LAESI mass spectrometry with plume collimation. ...

Jessica A. Stolee; Akos Vertes

2013-02-28T23:59:59.000Z

Note: This page contains sample records for the topic "kinetics laser ablation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

Kinetics of ion and prompt electron emission from laser-produced plasma  

SciTech Connect (OSTI)

We investigated ion emission dynamics of laser-produced plasma from several elements, comprised of metals and non-metals (C, Al, Si, Cu, Mo, Ta, W), under vacuum conditions using a Faraday cup. The estimated ion flux for various targets studied showed a decreasing tendency with increasing atomic mass. For metals, the ion flux is found to be a function of sublimation energy. A comparison of temporal ion profiles of various materials showed only high-Z elements exhibited multiple structures in the ion time of flight profile indicated by the observation of higher peak kinetic energies, which were absent for low-Z element targets. The slower ions were seen regardless of the atomic number of target material propagated with a kinetic energy of 15 keV, while the fast ions observed in high-Z materials possessed significantly higher energies. A systematic study of plasma properties employing fast photography, time, and space resolved optical emission spectroscopy, and electron analysis showed that there existed different mechanisms for generating ions in laser ablation plumes. The origin of high kinetic energy ions is related to prompt electron emission from high-Z targets.

Farid, N. [Center for Materials Under Extreme Environment, School of Nuclear Engineering, Purdue University, West Lafayette, Indiana 47907 (United States) [Center for Materials Under Extreme Environment, School of Nuclear Engineering, Purdue University, West Lafayette, Indiana 47907 (United States); Key Laboratory of Materials Modification by Laser, Ion and Electron Beams, School of Physics and Optical Engineering, Dalian University of Technology, Dalian (China); Harilal, S. S.; Hassanein, A. [Center for Materials Under Extreme Environment, School of Nuclear Engineering, Purdue University, West Lafayette, Indiana 47907 (United States)] [Center for Materials Under Extreme Environment, School of Nuclear Engineering, Purdue University, West Lafayette, Indiana 47907 (United States); Ding, H. [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams, School of Physics and Optical Engineering, Dalian University of Technology, Dalian (China)] [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams, School of Physics and Optical Engineering, Dalian University of Technology, Dalian (China)

2013-07-15T23:59:59.000Z

82

Combining Laser Ablation/Liquid Phase Collection Surface Sampling and High-Performance Liquid Chromatography Electrospray Ionization Mass Spectrometry  

SciTech Connect (OSTI)

This paper describes the coupling of ambient pressure transmission geometry laser ablation with a liquid phase sample collection method for surface sampling and ionization with subsequent mass spectral analysis. A commercially available autosampler was adapted to produce a liquid droplet at the end of the syringe injection needle while in close proximity to the surface to collect the sample plume produced by laser ablation. The sample collection was followed by either flow injection or a high performance liquid chromatography (HPLC) separation of the extracted components and detection with electrospray ionization mass spectrometry (ESI-MS). To illustrate the analytical utility of this coupling, thin films of a commercial ink sample containing rhodamine 6G and of mixed isobaric rhodamine B and 6G dyes on glass microscope slides were analyzed. The flow injection and HPLC/ESI-MS analysis revealed successful laser ablation, capture and, with HPLC, the separation of the two compounds. The ablated circular area was about 70 m in diameter for these experiments. The spatial sampling resolution afforded by the laser ablation, as well as the ability to use sample processing methods like HPLC between the sample collection and ionization steps, makes this combined surface sampling/ionization technique a highly versatile analytical tool.

Ovchinnikova, Olga S [ORNL; Kertesz, Vilmos [ORNL; Van Berkel, Gary J [ORNL

2011-01-01T23:59:59.000Z

83

Indirect-drive ablative Rayleigh-Taylor growth experiments on the Shenguang-II laser facility  

SciTech Connect (OSTI)

In this research, a series of single-mode, indirect-drive, ablative Rayleigh-Taylor (RT) instability experiments performed on the Shenguang-II laser facility [X. T. He and W. Y. Zhang, Eur. Phys. J. D 44, 227 (2007)] using planar target is reported. The simulation results from the one-dimensional hydrocode for the planar foil trajectory experiment indicate that the energy flux at the hohlraum wall is obviously less than that at the laser entrance hole. Furthermore, the non-Planckian spectra of x-ray source can strikingly affect the dynamics of the foil flight and the perturbation growth. Clear images recorded by an x-ray framing camera for the RT growth initiated by small- and large-amplitude perturbations are obtained. The observed onset of harmonic generation and transition from linear to nonlinear growth regime is well predicted by two-dimensional hydrocode simulations.

Wu, J. F.; Fan, Z. F.; Zheng, W. D.; Wang, M.; Pei, W. B.; Zhu, S. P.; Zhang, W. Y. [Institute of Applied Physics and Computational Mathematics, Beijing 100094 (China)] [Institute of Applied Physics and Computational Mathematics, Beijing 100094 (China); Miao, W. Y.; Yuan, Y. T.; Cao, Z. R.; Deng, B.; Jiang, S. E.; Liu, S. Y.; Ding, Y. K. [Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900 (China)] [Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900 (China); Wang, L. F.; Ye, W. H., E-mail: ye-wenhua@iapcm.ac.cn; He, X. T. [Institute of Applied Physics and Computational Mathematics, Beijing 100094 (China) [Institute of Applied Physics and Computational Mathematics, Beijing 100094 (China); HEDPS, Center for Applied Physics and Technology, Peking University, Beijing 100871 (China)

2014-04-15T23:59:59.000Z

84

Safeguards Verification Measurements using Laser Ablation, Absorbance Ratio Spectrometry in Gaseous Centrifuge Enrichment Plants  

SciTech Connect (OSTI)

Laser Ablation Absorbance Ratio Spectrometry (LAARS) is a new verification measurement technology under development at the US Department of Energys (DOE) Pacific Northwest National Laboratory (PNNL). LAARS uses three lasers to ablate and then measure the relative isotopic abundance of uranium compounds. An ablation laser is tightly focused on uranium-bearing solids producing a small plume containing uranium atoms. Two collinear wavelength-tuned spectrometry lasers transit through the plume and the absorbance of U-235 and U-238 isotopes are measured to determine U-235 enrichment. The measurement has high relative precision and detection limits approaching the femtogram range for uranium. It is independent of chemical form and degree of dilution with nuisance dust and other materials. High speed sample scanning and pinpoint characterization allow measurements on millions of particles/hour to detect and analyze the enrichment of trace uranium in samples. The spectrometer is assembled using commercially available components at comparatively low cost, and features a compact and low power design. Future designs can be engineered for reliable, autonomous deployment within an industrial plant environment. Two specific applications of the spectrometer are under development: 1) automated unattended aerosol sampling and analysis and 2) on-site small sample destructive assay measurement. The two applications propose game-changing technological advances in gaseous centrifuge enrichment plant (GCEP) safeguards verification. The aerosol measurement instrument, LAARS-environmental sampling (ES), collects aerosol particles from the plant environment in a purpose-built rotating drum impactor and then uses LAARS-ES to quickly scan the surface of the impactor to measure the enrichments of the captured particles. The current approach to plant misuse detection involves swipe sampling and offsite analysis. Though this approach is very robust it generally requires several months to obtain results from a given sample collection. The destructive assay instrument, LAARS-destructive assay (DA), uses a simple purpose-built fixture with a sampling planchet to collect adsorbed UF6 gas from a cylinder valve or from a process line tap or pigtail. A portable LAARS-DA instrument scans the microgram quantity of uranium collected on the planchet and the assay of the uranium is measured to ~0.15% relative precision. Currently, destructive assay samples for bias defect measurements are collected in small sample cylinders for offsite mass spectrometry measurement.

Anheier, Norman C.; Cannon, Bret D.; Qiao, Hong (Amy) [Amy; Phillips, Jon R.

2012-07-01T23:59:59.000Z

85

Dynamics of plasma expansion and shockwave formation in femtosecond laser-ablated aluminum plumes in argon gas at atmospheric pressures  

E-Print Network [OSTI]

plasma expansion into a background gas at atmospheric pressure is cru- cial for many engineeringDynamics of plasma expansion and shockwave formation in femtosecond laser-ablated aluminum plumes in argon gas at atmospheric pressures Alexander Miloshevsky, Sivanandan S. Harilal, Gennady Miloshevsky

Harilal, S. S.

86

Photoemission Studies of Metallic Photocathodes Prepared by Pulsed Laser Ablation Deposition Technique  

SciTech Connect (OSTI)

We present the results of our investigation on metallic films as suitable photocathodes for the production of intense electron beams in RF photoinjector guns. Pulsed laser ablation deposition technique was used for growing Mg and Y thin films onto Si and Cu substrates in high vacuum and at room temperature.Different diagnostic methods were used to characterize the thin films deposited on Si with the aim to optimize the deposition process. Photoelectron performances were investigated on samples deposited on Cu substrate in an ultra high vacuum photodiode chamber at 10{sup -7} Pa. Relatively high quantum efficiencies have been obtained for the deposited films, comparable to those of corresponding bulks. Samples could stay for several months in humid open air before being tested in a photodiode cell. The deposition process and the role of the photocathode surface contamination and its influence on the photoelectron performances are presented and discussed.

Fasano, V.; Lorusso, A.; Perrone, A. [National Institute of Nuclear Physics and Physics Department, University of Salento, Via Arnesano, 73100-Lecce (Italy); De Rosa, H. [Laboratorio de Metalografia, Dpto. Ingenieria Mecanica y Naval, Facultad de Ingenieria, Universidad de Buenos Aires (Argentina); Cultrera, L. [National Institute of Nuclear Physics, National Laboratories, Frascati (Italy)

2010-11-10T23:59:59.000Z

87

Low-temperature atmospheric pressure argon plasma treatment and hybrid laser-plasma ablation of barite crown and heavy flint glass  

Science Journals Connector (OSTI)

We report on atmospheric pressure argon plasma-based surface treatment and hybrid laser-plasma ablation of barite crown glass N-BaK4 and heavy flint glass SF5. By pure plasma...

Gerhard, Christoph; Roux, Sophie; Brckner, Stephan; Wieneke, Stephan; Vil, Wolfgang

2012-01-01T23:59:59.000Z

88

Thermodynamic pathways to melting, ablation, and solidification in absorbing solids under pulsed laser irradiation  

Science Journals Connector (OSTI)

The thermodynamic pathways involved in laser irradiation of absorbing solids are investigated in silicon for pulse durations of 500fs and 100ps. This is achieved by accounting for carrier and atom dynamics within a combined Monte Carlo and molecular-dynamics scheme and simultaneously tracking the time evolution of the irradiated material in ?-T-P space. Our simulations reveal thermal changes in long-range order and state of aggregation driven, in most cases, by nonequilibrium states of rapidly heated or promptly cooled matter. Under femtosecond irradiation near the ablation threshold, the system is originally pulled to a near-critical state following rapid (?10?12s) disordering of the mechanically unstable crystal and isochoric heating of the resulting metallic liquid. The latter is then adiabatically cooled to the liquid-vapor regime where phase explosion of the subcritical, superheated melt is initiated by a direct conversion of translational, mechanical energy into surface energy on a ?10?1210?11s time scale. At higher fluences, matter removal involves, instead, the fragmentation of an initially homogeneous fluid subjected to large strain rates upon rapid, supercritical expansion in vacuum. Under picosecond irradiation, homogeneous and, at later times, heterogeneous melting of the superheated solid are followed by nonisochoric heating of the molten metal. In this case, the subcritical liquid material is subsequently cooled onto the binodal by thermal conduction and explosive boiling does not take place; as a result, ablation is associated with a trivial fragmentation process, i.e., the relatively slow expansion and dissociation into liquid droplets of supercritical matter near thermodynamic equilibrium. This implies a liquid-vapor equilibration time of ?10?1110?10s and heating along the binodal under nanosecond irradiation. Solidification of the nonablated, supercooled molten material is eventually observed on a ?10?1110?9s time scale, irrespective of the pulse duration.

Patrick Lorazo; Laurent J. Lewis; Michel Meunier

2006-04-14T23:59:59.000Z

89

Campaign-style titanite UPb dating by laser-ablation ICP: Implications for crustal flow, phase transformations and titanite closure  

E-Print Network [OSTI]

Campaign-style titanite U­Pb dating by laser-ablation ICP: Implications for crustal flow, phase transformations and titanite closure K.J. Spencer a , B.R. Hacker a, , A.R.C. Kylander-Clark a , T.B. Andersen b Editor: K. Mezger Keywords: Titanite Ultrahigh-pressure U­Pb Norway U­Pb dates of titanite from >150

Hacker, Bradley R.

90

Multielement analysis of coal by ICP techniques using solution nebulization and laser ablation  

Science Journals Connector (OSTI)

The combination of inductively coupled plasma atomic emission spectrometry and high resolution inductively coupled plasma mass spectrometry for the determination of 70 elements in coal were studied. Four microwave-assisted digestion procedures with different dissolution mixtures (nitric and hydrofluoric acids, aqua regia and hydrogen peroxide), lithium metaborate fusion with and without previous sample ashing as well as direct sampling by laser ablation (LA) have been tested. Examples of spectral interferences are given and different correction procedures are discussed. Detection limits in the low ng g?1 range were obtained for most of the elements investigated by using high-purity reagents and by taking special care to prevent sample contamination during preparation. The precision was assessed from replicate analysis (including sample preparation) of coal samples and was found to be, as average values far all elements, 45% RSD and 1015% RSD for procedures including sample digestion and LA sampling, respectively. The accuracy of the overall analytical procedures was estimated by analysis of certified reference materials and of a coal sample obtained from the Interlab Trace round robin test. Among the dissolution mixtures tested, the combination of nitric and hydrofluoric acids with hydrogen peroxide provide the best agreement with certified, recommended, literature-compiled or consensus values, though fusion is necessary to obtain quantitative recoveries for Si, Cr, Hf, W, Zr, Y. In general, results obtained by LA fall within 20% of those obtained after digestion.

Ilia Rodushkin; Mikael D Axelsson; Erik Burman

2000-01-01T23:59:59.000Z

91

Isotopic Analysis of Uranium in NIST SRM Glass by Femtosecond Laser Ablation  

SciTech Connect (OSTI)

We employed femtosecond Laser Ablation Multicollector Inductively Coupled Mass Spectrometry for the 11 determination of uranium isotope ratios in a series of standard reference material glasses (NIST 610, 612, 614, and 12 616). This uranium concentration in this series of SRM glasses is a combination of isotopically natural uranium in 13 the materials used to make the glass matrix and isotopically depleted uranium added to increase the uranium 14 elemental concentration across the series. Results for NIST 610 are in excellent agreement with literature values. 15 However, other than atom percent 235U, little information is available for the remaining glasses. We present atom 16 percent and isotope ratios for 234U, 235U, 236U, and 238U for all four glasses. Our results show deviations from the 17 certificate values for the atom percent 235U, indicating the need for further examination of the uranium isotopes in 18 NIST 610-616. Our results are fully consistent with a two isotopic component mixing between the depleted 19 uranium spike and natural uranium in the bulk glass.

Duffin, Andrew M.; Hart, Garret L.; Hanlen, Richard C.; Eiden, Gregory C.

2013-05-19T23:59:59.000Z

92

ccsd-00001265(version1):10Mar2004 Applied Physics A (2004) accepted Silicon clusters produced by femtosecond laser ablation: Non-thermal emission and  

E-Print Network [OSTI]

by femtosecond laser ablation: Non-thermal emission and gas-phase condensation Alexander V. Bulgakov Institute mechanisms of cluster formation (Coulomb explosion, gas-phase condensation, phase explosion) are discussed sampled parallel to the plume axis by a 500 V repeller pulse at a time delay td in respect to the laser

Boyer, Edmond

93

Direct analysis of samples by mass spectrometry: From elements to bio-molecules using laser ablation inductively couple plasma mass spectrometry and laser desorption/ionization mass spectrometry  

SciTech Connect (OSTI)

Mass spectrometric methods that are able to analyze solid samples or biological materials with little or no sample preparation are invaluable to science as well as society. Fundamental research that has discovered experimental and instrumental parameters that inhibit fractionation effects that occur during the quantification of elemental species in solid samples by laser ablation inductively coupled plasma mass spectrometry is described. Research that determines the effectiveness of novel laser desorption/ionization mass spectrometric methods for the molecular analysis of biological tissues at atmospheric pressure and at high spatial resolution is also described. A spatial resolution is achieved that is able to analyze samples at the single cell level.

Perdian, David C.

2009-08-19T23:59:59.000Z

94

Calibration of laser ablation inductively coupled plasma mass spectrometry using dried solution aerosols for the quantitative analysis of solid samples  

SciTech Connect (OSTI)

Inductively coupled plasma mass spectrometry (ICP-MS) has become the method of choice for elemental and isotopic analysis. Several factors contribute to its success. Modern instruments are capable of routine analysis at part per trillion levels with relative detection limits in part per quadrillion levels. Sensitivities in these instruments can be as high as 200 million counts per second per part per million with linear dynamic ranges up to eight orders of magnitude. With standards for only a few elements, rapid semiquantitative analysis of over 70 elements in an individual sample can be performed. Less than 20 years after its inception ICP-MS has shown to be applicable to several areas of science. These include geochemistry, the nuclear industry, environmental chemistry, clinical chemistry, the semiconductor industry, and forensic chemistry. In this introduction, the general attributes of ICP-MS will be discussed in terms of instrumentation and sample introduction. The advantages and disadvantages of current systems are presented. A detailed description of one method of sample introduction, laser ablation, is given. The paper also gives conclusions and suggestions for future work. Chapter 2, Quantitative analysis of solids by laser ablation inductively coupled plasma mass spectrometry using dried solution aerosols for calibration, has been removed for separate processing.

Leach, J.

1999-02-12T23:59:59.000Z

95

Theory and numerical modeling of the accelerated expansion of laser-ablated materials near a solid surface  

Science Journals Connector (OSTI)

A self-similar theory and numerical hydrodynamic modeling is developed to investigate the effects of dynamic source and partial ionization on the acceleration of the unsteady expansion of laser-ablated material near a solid target surface. The dynamic source effect accelerates the expansion in the direction perpendicular to the target surface, while the dynamic partial ionization effect accelerates the expansion in all directions. The vaporized material during laser ablation provides a nonadiabatic dynamic source at the target surface into the unsteady expanding fluid. For studying the dynamic source effect, the self-similar theory begins with an assumed profile of plume velocity, u=v/vm=?+(1-?)?, where vm is the maximum expansion velocity, ? is a constant, and ?=x/vmt. The resultant profiles of plume density and plume temperature are derived. The relations obtained from the conservations of mass, momentum, and energy, respectively, all show that the maximum expansion velocity is inversely proportional to ?, where 1-? is the slope of plume velocity profile. The numerical hydrodynamic simulation is performed with the Rusanov method and the Newton Raphson method. The profiles and scalings obtained from numerical hydrodynamic modeling are in good agreement with the theory. The dynamic partial ionization requires ionization energy from the heat at the expansion front, and thus reduces the increase of front temperature. The reduction of thermal motion would increase the flow velocity to conserve the momentum. This dynamic partial ionization effect is studied with the numerical hydrodynamic simulation including the Saha equation. With these effects, ? is reduced from its value of conventional free expansion. This reduction on ? increases the flow velocity slope, decreases the flow velocity near the surface, and reduces the thermal motion of plume, such that the maximum expansion velocity is significantly increased over that found from conventional models. The result may provide an explanation for experimental observations of high-expansion front velocities even at low-laser fluence.

K. R. Chen; T. C. King; J. H. Hes; J. N. Leboeuf; D. B. Geohegan; R. F. Wood; A. A. Puretzky; J. M. Donato

1999-09-15T23:59:59.000Z

96

LT-UHV-STM/STS Study on Laser Ablated Nd1+xBa2-xCu3O7-? Superconducting Thin Films  

Science Journals Connector (OSTI)

We have succeeded in growing high quality Nd1+xBa2-xCu3O7-? superconducting thin films on SrTiO3...(100) by laser ablation technique. The structural and superconducting properties have been investigated by XRD, A...

R. Itti; M. Badaye; K. Matsumoto; Wu Ting; H. Nakaji

1996-01-01T23:59:59.000Z

97

Emission features of femtosecond laser ablated carbon plasma in ambient K. F. Al-Shboul, S. S. Harilal, and A. Hassanein  

E-Print Network [OSTI]

Emission features of femtosecond laser ablated carbon plasma in ambient helium K. F. Al-Shboul, S carbon species in the plume were obtained using time of flight emission spectroscopy. These contours 2013; published online 30 April 2013) We investigated the optical emission features of plasmas produced

Harilal, S. S.

98

E-Print Network 3.0 - ablation plume propagation Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Page: << < 1 2 3 4 5 > >> 1 Computational model for multiscale simulation of laser ablation Leonid V. Zhigilei Summary: of laser ablation, a combined MD - finite element...

99

Picosecond pulse laser ablation of yttria-stabilized zirconia fromkilohertz to megahertz repetition rates  

Science Journals Connector (OSTI)

Thin films of yttria stabilized zirconia were deposited onto silicon substrates using high repetition rate picosecond pulse lasers. The applied lasers covered the repetition rate range from 10kHz to 4MHz. We...

Turkka Salminen; Mikko Hahtala; Ilkka Seppl; Pekka Laukkanen

2010-12-01T23:59:59.000Z

100

In situ diagnostic of the size distribution of nanoparticles generated by ultrashort pulsed laser ablation in vacuum  

SciTech Connect (OSTI)

We aim to characterize the size distribution of nanoparticles located in the ablation plume produced by femtosecond laser interaction. The proposed method relies on the use of white-light extinction spectroscopy setup assisted by ultrafast intensified temporal gating. This method allows measurement of optical absorbance of a nickel nanoparticles cloud. Simulation of the extinction section of nickel nanoparticles size distributions has been developed in order to compare the measured optical absorbance to the optical extinction by theoretical and experimental nanoparticles size distributions (measured by scanning electron microscopy). A good agreement has been found between the in situ measured optical absorbance and the optical extinction cross section calculated from ex situ nanoparticles size distribution measurements.

Bourquard, Florent; Loir, Anne-Sophie; Donnet, Christophe; Garrelie, Florence, E-mail: florence.garrelie@univ-st-etienne.fr [Universit de Lyon, CNRS UMR 5516, Laboratoire Hubert Curien, Universit Jean Monnet, Saint-tienne (France)] [Universit de Lyon, CNRS UMR 5516, Laboratoire Hubert Curien, Universit Jean Monnet, Saint-tienne (France)

2014-03-10T23:59:59.000Z

Note: This page contains sample records for the topic "kinetics laser ablation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

Laser Ablation Sampling of Materials Directly into the Formed Liquid Microjunction of a Continuous Flow Surface Sampling Probe/Electrospray Ionization Emitter for Mass Spectral Analysis and Imaging  

SciTech Connect (OSTI)

Transmission geometry laser ablation directly into a formed liquid microjunction of a continuous flow liquid microjunction surface sampling probe/electrospray ionization emitter was utilized for molecular and elemental detection and mass spectrometry imaging. The ability to efficiently capture and ionize ablated material was demonstrated by the detection of various small soluble n-mers of polyaniline and silver ion solvent clusters formed from laser ablation of electropolymerized polyaniline and silver thin films, respectively. In addition, analysis of surfaces that contain soluble components was accomplished by coating or laminating the sample with an insoluble film to enable liquid junction formation without directly extracting material from the surface. The ability to perform mass spectrometry imaging at a spatial resolution of about 50 m was illustrated by using laminated inked patterns on a microscope slide. In general, these data demonstrate at least an order of magnitude signal enhancement compared to the non-contact, laser ablation droplet capture-based surface sampling/ionization approaches that have been previously presented.

Ovchinnikova, Olga S [ORNL] [ORNL; Lorenz, Matthias [ORNL] [ORNL; Kertesz, Vilmos [ORNL] [ORNL; Van Berkel, Gary J [ORNL] [ORNL

2013-01-01T23:59:59.000Z

102

High throughput solar cell ablation system  

DOE Patents [OSTI]

A solar cell is formed using a solar cell ablation system. The ablation system includes a single laser source and several laser scanners. The laser scanners include a master laser scanner, with the rest of the laser scanners being slaved to the master laser scanner. A laser beam from the laser source is split into several laser beams, with the laser beams being scanned onto corresponding wafers using the laser scanners in accordance with one or more patterns. The laser beams may be scanned on the wafers using the same or different power levels of the laser source.

Harley, Gabriel; Pass, Thomas; Cousins, Peter John; Viatella, John

2012-09-11T23:59:59.000Z

103

High throughput solar cell ablation system  

DOE Patents [OSTI]

A solar cell is formed using a solar cell ablation system. The ablation system includes a single laser source and several laser scanners. The laser scanners include a master laser scanner, with the rest of the laser scanners being slaved to the master laser scanner. A laser beam from the laser source is split into several laser beams, with the laser beams being scanned onto corresponding wafers using the laser scanners in accordance with one or more patterns. The laser beams may be scanned on the wafers using the same or different power levels of the laser source.

Harley, Gabriel; Pass, Thomas; Cousins, Peter John; Viatella, John

2014-10-14T23:59:59.000Z

104

In Situ Metabolic Profiling of Single Cells by Laser Ablation Electrospray Ionization Mass Spectrometry  

Science Journals Connector (OSTI)

Further removal of the fiber tip from the cell surface resulted in no ablation, whereas closer approach often led to damage to the cell or the fiber tip. ... Ten organic purple A. cepa bulbs (5?7 cm transverse diameter) were purchased from a local store (distributed by CFF Fresh, Sedro-Woolley, WA and bought in Washington, DC), and four N. pseudonarcissus bulb were obtained from Reston, VA. ... For sodium and potassium, or any other ionic species, charge displacement of a fluorescent cation results in indirect fluorescence detection. ...

Bindesh Shrestha; Akos Vertes

2009-09-17T23:59:59.000Z

105

Nanosecond laser-induced selective removal of the active layer of CuInGaSe2 solar cells by stress-assisted ablation  

Science Journals Connector (OSTI)

We demonstrate that laser pulses of nanosecond duration (?=1064 nm, ?=25 ns, PRR =5 kHz) are capable of the clean removal of the CuInGaSe2 (CIGS) and ZnO:Al layers in the layer structure of chalcogenide-based solar cells, leaving the underlying Mo layer undamaged and producing excellent crater morphology. Our results prove that the material removal process is governed by the thermomechanical stress developing in the CIGS layer due to rapid laser heating. In the mechanical ablation of the active layer, three phenomena play a crucial role, namely, delamination, buckling, and fracture. Morphological and compositional analysis of the laser-processed areas is used to identify the experimental parameters where clean mechanical ablation can be achieved. Numerical calculations, performed in the comsol software environment, are also presented to complement the experimental tendencies and verify the proposed model. Our calculation proves the development of a stress distribution that drives the delamination of the CIGS and Mo layers. As the delamination front proceeds radially outward, the separation of the layers ceases in the colder outer regions according to the Griffith's criterion and defines the size of the craters produced afterwards. The free-standing chalcogenide layer continues to deform, and buckling results in a growing tensile stress at the perimeter of the delaminated area, where ultimately fracture will finalize the removal process and facilitate the clean ablation of the laser-irradiated area.

Andrs Buzs and Zsolt Geretovszky

2012-06-07T23:59:59.000Z

106

Investigations of the plume accompanying pulsed ultraviolet laser ablation of graphite in vacuum  

E-Print Network [OSTI]

, and subsequent radiative cascade from the high n,l Rydberg states that result. The distribution of C neutral be accommodated, re- bound back into the gas phase, or induce surface modification via sputtering, compaction, the laser­target interac- tions will be sensitively dependent both on the nature and condition of the target

Bristol, University of

107

Characterization of hydrocarbon and mixed layers in TEXTOR by laser induced ablation spectroscopy  

E-Print Network [OSTI]

: 134.95.83.67 The article was downloaded on 10/03/2012 at 13:13 Please note that terms and conditions apply. View the table of contents for this issue, or go to the journal homepage for more Home Search the plasma discharge by intense laser radiation. The light emitted by particles entering the edge

Giesen, Thomas

108

Investigation of optical limiting properties of Aluminium nanoparticles prepared by pulsed laser ablation in different carrier media  

SciTech Connect (OSTI)

In this communication, we carried out the systematic investigation of nonlinear absorption and scattering properties of Aluminium nanoparticles (Al NPs) in various polar and non-polar solvents. Al NPs were synthesized with pulsed Nd:YAG laser operated at 1064 nm by ablating Al target in polar and non-polar liquid environment like chloroform, chlorobenzene, toluene, benzene, and carbon tetrachloride. Synthesized Al NPs colloids of various solvents differ in appearance and UV-Vis extinction spectra exhibit absorption in the UV region. The characterization of Al NPs performed by Transmission electron microscopy (TEM) studies reveal that NPs are made up of a well crystallized Al inner part (bright zone) embedded with an amorphous metal Al shell (dark region). Growth, aggregation, and precipitation mechanisms which influence the optical properties and stability of NPs are found to be related to the dipole moment of the surrounding liquid environment. The nonlinear absorption and scattering studies are performed by open aperture Z-scan technique with 532 nm under nanosecond pulse excitation. The Z-scan measurements are fitted theoretically to estimate both two-photon absorption (TPA) and nonlinear scattering (NLS) coefficients. In polar solvents like chlorobenzene, chloroform synthesized Al NPs exhibited higher TPA, NLS coefficient values, and lower optical limiting threshold values in comparison with partially polar solvent like toluene and non-polar solvents like benzene and carbontetrachloride. These results indicate the potential use of Al NPs as a versatile optical limiting material.

Kuladeep, Rajamudili; Jyothi, L.; Narayana Rao, D. [School of Physics, University of Hyderabad, Prof. C. R. Rao Road, Hyderabad 500046 (India)] [School of Physics, University of Hyderabad, Prof. C. R. Rao Road, Hyderabad 500046 (India); Prakash, P.; Mayank Shekhar, S. [Center of Excellence in Lasers and Optoelectronic Sciences, International School of Photonics, Cochin University of Science and Technology, Kochi (India)] [Center of Excellence in Lasers and Optoelectronic Sciences, International School of Photonics, Cochin University of Science and Technology, Kochi (India); Durga Prasad, M. [Center for Nanotechnology, University of Hyderabad, Prof. C. R. Rao Road, Hyderabad 500046 (India)] [Center for Nanotechnology, University of Hyderabad, Prof. C. R. Rao Road, Hyderabad 500046 (India)

2013-12-28T23:59:59.000Z

109

Nanostructured europium oxide thin films deposited by pulsed laser ablation of a metallic target in a He buffer atmosphere  

SciTech Connect (OSTI)

Nanostrucured europium oxide and hydroxide films were obtained by pulsed Nd:YAG (532 nm) laser ablation of a europium metallic target, in the presence of a 1 mbar helium buffer atmosphere. Both the produced film and the ambient plasma were characterized. The plasma was monitored by an electrostatic probe, for plume expansion in vacuum or in the presence of the buffer atmosphere. The time evolution of the ion saturation current was obtained for several probe to substrate distances. The results show the splitting of the plume into two velocity groups, being the lower velocity profile associated with metal cluster formation within the plume. The films were obtained in the presence of helium atmosphere, for several target-to-substrate distances. They were analyzed by Rutherford backscattering spectrometry, x-ray diffraction, and atomic force microscopy, for as-deposited and 600 deg. C treated-in-air samples. The results show that the as-deposited samples are amorphous and have chemical composition compatible with europium hydroxide. The thermally treated samples show x-ray diffraction peaks of Eu{sub 2}O{sub 3}, with chemical composition showing excess oxygen. Film nanostructuring was shown to be strongly correlated with cluster formation, as shown by velocity splitting in probe current versus time plots.

Luna, H.; Franceschini, D. F.; Prioli, R.; Guimaraes, R. B.; Sanchez, C. M.; Canal, G. P.; Barbosa, M. D. L.; Galvao, R. M. O. [Instituto de Fisica, Universidade Federal do Rio de Janeiro, Cx. Postal 68528, Rio de Janeiro, RJ 21941-972 (Brazil); Instituto de Fisica, Universidade Federal Fluminense, Niteroi, RJ 24210-346 (Brazil); Departamento de Fisica, Pontificia Universidade Catolica do Rio de Janeiro, Rua Marques de Sao Vicente 225, 22453-970, Rio de Janeiro, RJ (Brazil); Instituto de Fisica, Universidade Federal Fluminense, Niteroi, RJ 24210-346 (Brazil); Centro Brasileiro de Pesquisas Fisicas, Laboratorio de Plasmas Aplicados, Rua Xavier Sigaud 150, 22290-180, Rio de Janeiro, RJ (Brazil); Instituto de Fisica, Departamento de Fisica Nuclear, Universidade de Sao Paulo, Caixa Postal 66328, 05315-970, Sao Paulo, SP (Brazil); Centro Brasileiro de Pesquisas Fisicas, Laboratorio de Plasmas Aplicados, Rua Xavier Sigaud 150, 22290-180, Rio de Janeiro, RJ (Brazil)

2010-09-15T23:59:59.000Z

110

Unphysical kinetic effects in particle-in-cell modeling of laser wakefield accelerators Estelle Cormier-Michel,1,2  

E-Print Network [OSTI]

Unphysical kinetic effects in particle-in-cell modeling of laser wakefield accelerators Estelle of laser wakefield accelerators using particle-in-cell codes are investigated. A dark current free laser wakefield accelerator stage, in which no trapping of background plasma electrons into the plasma wave should

Geddes, Cameron Guy Robinson

111

Investigation of gain kinetics in a CO gas dynamic laser  

SciTech Connect (OSTI)

A detailed experimental investigation of small-signal gain in a CO gasdynamic laser, produced in a shock tunnel is presented. Gains of the P/sub 7/(3) transition were measured at a distance 44 cm downstream from the nozzle throat for various CO--Ar and CO--N/sub 2/--Ar mixtures at stagnation temperatures of 1800/sup 0/--3800 /sup 0/K and stagnation pressures of 18--40 atm. Optimum gas temperatures and compositions were observed. Laser oscillations were observed simultaneously in two cavities located at 44 and 56 cm downstream from the nozzle throat. The experimental data on gain have been compared with a numerical model. A quantitatively good argeement between calculations and experiments was found which permits the utilization of the mathematical model for a better understanding of the processes involved in the laser operation. Small signal gains and multi-line laser power outputs were calculated along the nozzle for various initial conditions. Calculations indicate that maximum gain and maximum power occur for P/sub 3/(4)-P/sub 5/(4) lines at a stagnation temperature of about 3000 /sup 0/K and a gas composition of CO:Ar = 20:80.

Stricker, J.; Tilleman, M.

1982-06-01T23:59:59.000Z

112

E-Print Network 3.0 - ablative thermal protection Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Page: << < 1 2 3 4 5 > >> 1 Analyses of femtosecond laser ablation of Ti, Zr and Hf. D. Grojo, J. Hermann* Summary: like thermal ablation 2, electrostatic ablation 3,...

113

Current developments in laser ablation-inductively coupled plasma-mass spectrometry for use in geology, forensics, and nuclear nonproliferation research  

SciTech Connect (OSTI)

This dissertation focused on new applications of laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The diverse fields that were investigated show the versatility of the technique. In Chapter 2, LA-ICP-MS was used to investigate the rare earth element (REE) profiles of garnets from the Broken Hill Deposit in New South Wales, Australia. The normalized REE profiles helped to shed new light on the formation of deposits of sulfide ores. This information may be helpful in identifying the location of sulfide ore deposits in other locations. New sources of metals such as Pg, Zn, and Ag, produced from these ores, are needed to sustain our current technological society. The application of LA-ICP-MS presented in Chapter 3 is the forensics analysis of automotive putty and caulking. The elemental analysis of these materials was combined with the use of Principal Components Analysis (PCA). The PCA comparison was able to differentiate the automotive putty samples by manufacturer and lot number. The analysis of caulk was able to show a differentiation based on manufacturer, but no clear differentiation was shown by lot number. This differentiation may allow matching of evidence in the future. This will require many more analyses and the construction of a database made up of many different samples. The 4th chapter was a study of the capabilities of LA-ICP-MS for fast and precise analysis of particle ensembles for nuclear nonproliferation applications. Laser ablation has the ability to spatially resolve particle ensembles which may contain uranium or other actinides from other particles present in a sample. This is of importance in samples obtained from air on filter media. The particle ensembles of interest may be mixed in amongst dust and other particulates. A problem arises when ablating these particle ensembles directly from the filter media. Dust particles other than ones of interest may be accidentally entrained in the aerosol of the ablated particle ensemble. This would cause the analysis to be skewed. The use of a gelatin substrate allows the ablation a particle ensemble without disturbing other particles or the gelatin surface. A method to trap and ablate particles on filter paper using collodion was also investigated. The laser was used to dig through the collodion layer and into the particle ensemble. Both of these methods fix particles to allow spatial resolution of the particle ensembles. The use of vanillic acid as a possible enhancement to ablation was also studied. A vanillic acid coating of the particles fixed on top of the gelatin substrate was not found to have any positive effect on either signal intensity or precision. The mixing of vanillic acid in the collodion solution used to coat the filter paper increased ablation signal intensity by a factor of 4 to 5. There was little effect on precision, though. The collodion on filter paper method and the gelatin method of resolving particles have shown themselves to be possible tools in fighting proliferation of nuclear weapons and material. Future applications of LA-ICP-MS are only limited by the imagination of the investigator. Any material that can be ablated and aerosolized is a potential material for analysis by LA-ICP-MS. Improvements in aerosol transport, ablation chamber design, and laser focusing can make possible the ablation and analysis of very small amounts of material. This may perhaps lead to more possible uses in forensics. A similar method to the one used in Chapter 3 could perhaps be used to match drug residue to the place of origin. Perhaps a link could be made based on the elements leached from the soil by plants used to make drugs. This may have a specific pattern based on where the plant was grown. Synthetic drugs are produced in clandestine laboratories that are often times very dirty. The dust, debris, and unique materials in the lab environment could create enough variance to perhaps match drugs produced there to samples obtained off the street. Even if the match was not strong enough to be evidence, the knowledge that many sa

Messerly, Joshua D.

2008-08-26T23:59:59.000Z

114

Development of an on-line isotope dilution laser ablation inductively coupled plasma mass spectrometry (LAICP-MS) method for determination of boron in silicon wafers  

Science Journals Connector (OSTI)

A method has been developed based on an on-line isotope dilution technique couple with laser ablation/inductively coupled plasma mass spectrometry (LAICP-MS), for the determination of boron in p-type silicon wafers. The laser-ablated sample aerosol was mixed on-line with an enriched boron aerosol supplied continuously using a conventional nebulization system. Upon mixing the two aerosol streams, the isotope ratio of boron changed rapidly and was then recorded by the ICP-MS system for subsequent quantification based on the isotope dilution principle. As an on-line solid analysis method, this system accurately quantifies boron concentrations in silicon wafers without the need for an internal or external solid reference standard material. Using this on-line isotope dilution technique, the limit of detection for boron in silicon wafers is 2.8נ1015atomscm?3. The analytical results obtained using this on-line methodology agree well with those obtained using wet chemical digestion methods for the analysis of p-type silicon wafers containing boron concentrations ranging from 1.0נ1016 to 9.6נ1018atomscm?3.

Chao-Kai Yang; Po-Hsiang Chi; Yong-Chine Lin; Yuh-Chang Sun; Mo-Hsiung Yang

2010-01-01T23:59:59.000Z

115

Infrared Spectra of M-?2-C2H2, HMC?CH, and HMC?CH Prepared in Reactions of Laser-Ablated Group 3 Metal Atoms with Acetylene  

Science Journals Connector (OSTI)

The major HMC?CH and M-?2-C2H2 products are observed in the matrix infrared spectra from reactions of laser-ablated group 3 metal atoms with acetylene, while the vinylidene product is not detected. These results reveal that coordination of group 3 metal ...

Han-Gook Cho; Lester Andrews

2012-09-25T23:59:59.000Z

116

Ablation of film stacks in solar cell fabrication processes  

DOE Patents [OSTI]

A dielectric film stack of a solar cell is ablated using a laser. The dielectric film stack includes a layer that is absorptive in a wavelength of operation of the laser source. The laser source, which fires laser pulses at a pulse repetition rate, is configured to ablate the film stack to expose an underlying layer of material. The laser source may be configured to fire a burst of two laser pulses or a single temporally asymmetric laser pulse within a single pulse repetition to achieve complete ablation in a single step.

Harley, Gabriel; Kim, Taeseok; Cousins, Peter John

2013-04-02T23:59:59.000Z

117

Peak effect in laser ablated DyBa2Cu3O7-d films at microwave frequencies at subcritical currents  

E-Print Network [OSTI]

In this paper we report the observation of a peak in the microwave surface resistance (at frequencies ~10GHz) of laser ablated DyBa2Cu3O7-d films in magnetic field ranging from 2 to 9kOe (||c) close to the superconducting transition temperature (Tc(H)). The exact nature of peak is sample dependent but it follows a general behaviour. The peak shifts to lower temperature when the magnetic field is increased. It has strong frequency dependence and the peak is pronounced at frequencies close to the depinning frequency of the flux line lattice. From the observed temperature and field dependence we argue that this peak is associated with the order disorder transition of the flux line lattice close to Tc(H).

A. R. Bhangale; P. Raychaudhuri; T. Banerjee; R. Pinto; V. S. Shirodhkar

2000-11-16T23:59:59.000Z

118

Comparison of Time-of-flight and Multicollector ICP Mass Spectrometers for Measuring Actinides in Small Samples using single shot Laser Ablations  

SciTech Connect (OSTI)

The objective of these experiments is to evaluate the performance of two types of ICP-MS device for measurement of actinide isotopes by laser ablation (LA) ICP-MS. The key advantage of ICP-MS compared to monitoring of radioactive decay is that the element need not decay during the measurement time. Hence ICP-MS is much faster for long-lived radionuclides. The LA process yields a transient signal. When spatially resolved analysis is required for small samples, the laser ablation sample pulse lasts only {approx}10 seconds. It is difficult to measure signals at several isotopes with analyzers that are scanned for such a short sample transient. In this work, a time-of-flight (TOF) ICP-MS device, the GBC Optimass 8000 (Figure 1) is one instrument used. Strictly speaking, ions at different m/z values are not measured simultaneously in TOF. However, they are measured in very rapid sequence with little or no compromise between the number of m/z values monitored and the performance. Ions can be measured throughout the m/z range in single sample transients by TOF. The other ICP-MS instrument used is a magnetic sector multicollector MS, the NU Plasma 1700 (Figure 2). Up to 8 adjacent m/z values can be monitored at one setting of the magnetic field and accelerating voltage. Three of these m/z values can be measured with an electron multiplier. This device is usually used for high precision isotope ratio measurements with the Faraday cup detectors. The electron multipliers have much higher sensitivity. In our experience with the scanning magnetic sector instrument in Ames, these devices have the highest sensitivity and lowest background of any ICP-MS device. The ability to monitor several ions simultaneously, or nearly so, should make these devices valuable for the intended application: measurement of actinide isotopes at low concentrations in very small samples for nonproliferation purposes. The primary sample analyzed was an urban dust pellet reference material, NIST 1648. The ability to provide good detection limits for single laser shots is critical.

R.S. Houk; D.B. Aeschliman; S.J. Bajic; D. Baldwin

2005-11-01T23:59:59.000Z

119

Analysis of the structure, configuration, and sizing of Cu and Cu oxide nanoparticles generated by fs laser ablation of solid target in liquids  

SciTech Connect (OSTI)

We report on the analysis of structure, configuration, and sizing of Cu and Cu oxide nanoparticles (Nps) produced by femtosecond (fs) laser ablation of solid copper target in liquids. Laser pulse energy ranged between 500 {mu}J and 50 {mu}J. Water and acetone were used to produce the colloidal suspensions. The study was performed through optical extinction spectroscopy using Mie theory to fit the full experimental spectra, considering free and bound electrons size dependent contributions to the metal dielectric function. Raman spectroscopy and AFM technique were also used to characterize the sample. Considering the possible oxidation of copper during the fabrication process, two species (Cu and Cu{sub 2}O) arranged in two structures (bare core or core-shell) and in two configuration types (Cu-Cu{sub 2}O or Cu{sub 2}O-Cu) were considered for the fitting depending on the laser pulse energy and the surrounding media. For water at high energy, it can be observed that a Cu-Cu{sub 2}O configuration fits the experimental spectra of the colloidal suspension, while for decreasing energy and below a certain threshold, a Cu{sub 2}O-Cu configuration needs to be included for the optimum fit. Both species coexist for energies below 170 {mu}J for water. On the other hand, for acetone at high energy, optimum fit of the full spectrum suggests the presence a bimodal Cu-Cu{sub 2}O core-shell Nps distribution while for decreasing energy and below a 70 {mu}J threshold energy value, Cu{sub 2}O-Cu core-shell Nps must be included, together with the former configuration, for the fit of the full spectrum. We discuss possible reasons for the changes in the structural configuration of the core-shell Nps.

Santillan, J. M. J. [Centro de Investigaciones Opticas (CIOp), (CONICET La Plata - CIC) (Argentina); Videla, F. A.; Schinca, D. C.; Scaffardi, L. B. [Centro de Investigaciones Opticas (CIOp), (CONICET La Plata - CIC) (Argentina); Departamento de Ciencias Basicas, Facultad de Ingenieria, UNLP (Argentina); Fernandez van Raap, M. B. [Departamento de Fisica-IFLP, Universidad Nacional de La Plata-CONICET, L. B. Scaffardi: CIOp CC3 (1897) Gonnet, La Plata (Argentina)

2013-04-07T23:59:59.000Z

120

E-Print Network 3.0 - ablation technique possibilities Sample...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Summary: r is as small as possible, letting ablator r slow down the protons. To keep the laser plasma... Diagnosing ablator burn through in ignition capsules using D2+3 He gas...

Note: This page contains sample records for the topic "kinetics laser ablation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

Laser ablation/ionization characterization of solids: Second interim progress report of the strategic environmental research development program  

SciTech Connect (OSTI)

The Department of Energy is undertaking the enormous task of remediating defense wastes and environmental insults which have occurred over 50 years of nuclear weapons production. It is abundantly clear that significant technology advances are needed to characterize, process, and store highly radioactive waste and to remediate contaminated zones. In addition to the processing and waste form issues, analytical technologies needed for the characterization of solids, and for monitoring storage tanks and contaminated sites do not exist or are currently expensive labor-intensive tasks. This report describes progress in developing sensitive, rapid, and widely applicable laser-based mass spectrometry techniques for analysis of mixed chemical wastes and contaminated soils.

Hess, W.P.; Bushaw, B.A.; McCarthy, M.I.; Campbell, J.A.; Colson, S.D. [Pacific Northwest National Lab., Richland, WA (United States); Dickinson, J.T. [Washington State Univ., Pullman, WA (United States). Dept. of Physics

1996-10-01T23:59:59.000Z

122

E-Print Network 3.0 - ablation caracterizacion estructural Sample...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

at San Diego Collection: Plasma Physics and Fusion 82 Analyses of femtosecond laser ablation of Ti, Zr and Hf. D. Grojo, J. Hermann* Summary: Analyses of femtosecond...

123

E-Print Network 3.0 - ablation plume thermalization Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Universitt Duisburg-Essen Collection: Physics 31 Stagnation of Ablated Metal Vapor in Laser Fusion Reactor with Liquid Wall Summary: materials was calculated with ACONPL...

124

E-Print Network 3.0 - ablation ion-storage time-of-flight Sample...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Chemistry Collection: Geosciences 5 Analyses of femtosecond laser ablation of Ti, Zr and Hf. D. Grojo, J. Hermann* Summary: spectroscopy was employed to perform time-of-flight...

125

E-Print Network 3.0 - ablation electrode-induced displacement...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Plasma Fueling Group Collection: Plasma Physics and Fusion 7 Analyses of femtosecond laser ablation of Ti, Zr and Hf. D. Grojo, J. Hermann* Summary: Analyses of femtosecond...

126

E-Print Network 3.0 - ablation system kit Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

at San Diego Collection: Plasma Physics and Fusion 62 Analyses of femtosecond laser ablation of Ti, Zr and Hf. D. Grojo, J. Hermann* Summary: Analyses of femtosecond...

127

Graphene oxide-based micropatterns via high-throughput multiphoton-induced reduction and ablation  

Science Journals Connector (OSTI)

In this study, a developed temporal focusing-based femtosecond laser system provides high-throughput multiphoton-induced reduction and ablation of graphene oxide (GO) films. Integrated...

Li, Yi-Cheng; Yeh, Te-Fu; Huang, Hsin-Chieh; Chang, Hsin-Yu; Lin, Chun-Yu; Cheng, Li-Chung; Chang, Chia-Yuan; Teng, Hsisheng; Chen, Shean-Jen

2014-01-01T23:59:59.000Z

128

Ultrafast Infrared Heating Laser Pulse-Induced Micellization Kinetics of Poly(ethylene oxide)-Poly(propylene oxide)-Poly(ethylene oxide) in  

E-Print Network [OSTI]

Ultrafast Infrared Heating Laser Pulse-Induced Micellization Kinetics of Poly(ethylene oxide)-Poly(propylene oxide)-Poly(ethylene oxide) in Water Xiaodong Ye, Yijie Lu, Shilin Liu,*, Guangzhao Zhang, and Chi Wu-induced micellization of poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) (Pluronic PE10300) triblock

Liu, Shilin

129

Kinetics of laser pulse vaporization of uranium dioxide by mass spectrometry  

SciTech Connect (OSTI)

Safety analyses of nuclear reactors require knowledge of the evaporation behavior of UO/sub 2/ at temperatures well above the melting point of 3140 K. In this study, rapid transient heating of a small spot on a UO/sub 2/ specimen was accomplished by a laser pulse, which generates a surface temperature excursion. This in turn vaporizes the target surface and the gas expands into vacuum. The surface temperature transient was monitored by a fast-response automatic optical pyrometer. The maximum surface temperatures investigated range from approx. 3700 K to approx. 4300 K. A computer program was developed to simulate the laser heating process and calculate the surface temperature evolution. The effect of the uncertainties of the high temperature material properties on the calculation was included in a sensitivity study for UO/sub 2/ vaporization. The measured surface temperatures were in satisfactory agreements.

Tsai, C.

1981-11-01T23:59:59.000Z

130

Photoluminescent silicon nanocrystals synthesized by reactive laser Daria Riabinina,a  

E-Print Network [OSTI]

Photoluminescent silicon nanocrystals synthesized by reactive laser ablation Daria Riabinina reactive laser ablation in oxygen atmosphere followed by annealing. We observe a strong photoluminescence size, obtained independently by fitting photoluminescence spectra and from x-ray diffraction patterns

131

Surfaces/Solids Instrumentation with Lasers | EMSL  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

equipment and at EMSL must be performed in compliance with EMSL practices and permits. UHV Laser DesorptionAblation Apparatus In EMSL's energetic processes laboratory,...

132

Energetic Processes Instrumentation w/ Lasers | EMSL  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

equipment and at EMSL must be performed in compliance with EMSL practices and permits. UHV Laser DesorptionAblation Apparatus In EMSL's energetic processes laboratory,...

133

Laser Induced Breakdown Spectroscopy to Detect Copper Contamination in Transformer Insulation  

Science Journals Connector (OSTI)

Laser Induced Breakdown Spectroscopy combined with a laser-ablation based depth profiling technique is demonstrated for the detection of copper contamination in transformer insulation....

Aparna, N; Wazeem, M A; Vasa, Nilesh J; Sarathi, R; Sundara Rajan, J

134

Ablation by short optical and X-ray laser pulses N.A. Inogamova, S.I. Anisimova, V.V. Zhakhovskyb,c, A.Ya. Faenovb,d, Yu.V. Petrova,  

E-Print Network [OSTI]

concerning low value of ablation threshold are similar. Low value means high efficiency of short pulse XRL Academy of Sciences, Chernogolovka 142432, Russia; bJoint Institute for High Temperatures, Russian Academy ABSTRACT The paper is devoted to experimental and theoretical studies of ablation of condensed matter

Fominov, Yakov

135

Comparison of optical emission from nanosecond and femtosecond laser produced plasma in atmosphere and vacuum conditions  

E-Print Network [OSTI]

Comparison of optical emission from nanosecond and femtosecond laser produced plasma in atmosphere Laser-induced breakdown spectroscopy Laser-produced plasma Plasma dynamics Femtosecond laser ablation In this study we examine the emission from brass plasma produced by ns and fs laser ablation under both vacuum

Harilal, S. S.

136

Laser surface cleaning  

SciTech Connect (OSTI)

Decontamination of contaminated metal and material recycle, two of 31 priority needs identified by the D&D focus group, are the most promising applications for laser ablation within the DOE complex. F2 Associates has developed a robotic laser ablation system that is capable of high contamination rates, waste volume reduction, surface pore cleaning, and real-time characterization of materials. It is being demonstrated that this system will be the most cost-effective technology for metal decontamination and material recycle.

Crivella, E.C.; Freiwald, J.; Freiwald, D.A.

1996-12-31T23:59:59.000Z

137

E-Print Network 3.0 - ablation multi-collector inductively Sample...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

; Engineering 53 SIDEROPHILE ELEMENT PROFILE MEASUREMENTS IN IRON METEORITES USING LASER ABLATION ICP-MS. H.C. Watson1 Summary: possible, with the advent of high-resolution...

138

E-Print Network 3.0 - ablation plumes produced Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Science 14 University of California, San Diego UCSD-ENG-098 Fusion Division Summary: of Laser Ablation Plumes into Ambient Gases S. S. Harilal, C. V. Bindhu, M. S. Tillack, F....

139

Excimer kinetics and multiline model for the electron-beam pumped XeF(B-X) laser  

SciTech Connect (OSTI)

A physical model of the time-, temperature- and wavelength-dependent behavior of an E-beam pumped XeF(B-X) laser is developed. Correlations with published laser- and fluorescence-efficiency data, laser spectra, gain, and absorption data are discussed.

Blauer, J.A.; Yang, T.T.; Turner C.E. Jr.; Copeland, D.A.

1984-12-01T23:59:59.000Z

140

Plastic ablator ignition capsule design for the National Ignition Facility  

SciTech Connect (OSTI)

This paper describes current efforts to develop a plastic ablator capsule design for the first ignition attempt on the National Ignition Facility. The trade-offs in capsule scale and laser energy that must be made to achieve ignition probabilities comparable to those with other candidate ablators, beryllium and high-density carbon, are emphasized. Large numbers of 1-D simulations, meant to assess the statistical behavior of the target design, as well as 2-D simulations to assess the target's susceptibility to Rayleigh-Taylor growth are discussed.

Clark, D S; Haan, S W; Hammel, B A; Salmonson, J D; Callahan, D A; Town, R J

2009-10-06T23:59:59.000Z

Note: This page contains sample records for the topic "kinetics laser ablation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

High pressure generation by hot electrons driven ablation  

SciTech Connect (OSTI)

A previous model [Piriz et al. Phys. Plasmas 19, 122705 (2012)] for the ablation driven by the hot electrons generated in collisionless laser-plasma interactions in the framework of shock ignition is revisited. The impact of recent results indicating that for a laser wavelength ? = 0.35 ?m the hot electron temperature ?{sub H} would be independent of the laser intensity I, on the resulting ablation pressure is considered. In comparison with the case when the scaling law ?{sub H}?(I?{sup 2}){sup 1/3} is assumed, the generation of the high pressures needed for driving the ignitor shock may be more demanding. Intensities above 10{sup 17} W/cm{sup 2} would be required for ?{sub H}=25?30 keV.

Piriz, A. R. [E.T.S.I. Industriales, CYTEMA, and Instituto de Investigaciones Energticas, Universidad de Castilla-La Mancha, 13071 Ciudad Real (Spain)] [E.T.S.I. Industriales, CYTEMA, and Instituto de Investigaciones Energticas, Universidad de Castilla-La Mancha, 13071 Ciudad Real (Spain); Piriz, S. A. [Facultad de Ciencias Fsicas, Universidad Complutense de Madrid, 28040 Madrid (Spain)] [Facultad de Ciencias Fsicas, Universidad Complutense de Madrid, 28040 Madrid (Spain); Tahir, N. A. [GSI Helmholtzzentrum fr Schwerionenforschung, Planckstrasse 1, 64291 Darmstadt (Germany)] [GSI Helmholtzzentrum fr Schwerionenforschung, Planckstrasse 1, 64291 Darmstadt (Germany)

2013-11-15T23:59:59.000Z

142

Radiative ablation to low-Z matter  

Science Journals Connector (OSTI)

Eight beams of 0.35-?m laser with pulse duration of about 1.0 ns and energy of 260 J per beam were injected into a cylindrical cavity to generate intense x-ray radiation on the Shengguang II high power laser facility. Plastic foils with a thickness in the range of about 3.045 ?m were attached on the diagnostic hole of the cavity and ablated by the intense x-ray radiation. The radiative energy transport through plastic foils with different thicknesses has been studied experimentally. The burn-through time of the plastic foils has been obtained. For comparison, we also simulated the experimental results with Planckian and non-Planckian x-ray spectrum source, respectively. It is shown that for thick plastic foil the simulation with non-Planckian x-ray spectrum source is in good agreement with the experiment.

Jiamin Yang; Jiatian Sheng; Yaonan Ding; Yunsheng Li; Shaoen Jiang; Tinggui Feng; Zhijian Zheng; Kexu Sun; Wenghai Zhang; Yanli Cui; Jiushen Cheng

2002-09-30T23:59:59.000Z

143

Laser resonance heating of atoms in a capillary. Measuring the accommodation coefficient of the kinetic energy of the atoms  

Science Journals Connector (OSTI)

It has been experimentally detected that the laser irradiation of a rarefied flux of atoms in a capillary causes a reduction of their concentration at the output. It is established...

Bonch-Bruevich, A M; Vartanyan, T A; Przhibel'skii, S G; Smirnov, V N; Khromov, V V

2004-01-01T23:59:59.000Z

144

High-temperature iso-butene absorption diagnostic for shock tube kinetics using a pulsed quantum cascade laser near 11.3?m  

Science Journals Connector (OSTI)

Abstract A high-bandwidth absorption sensing technique for iso-butene (iC4H8) was developed to measure transient species concentration behind reflected shock waves for combustion kinetics studies. Direct measurements of iC4H8 were enabled by monitoring absorption in the infrared near 11.3?m using a novel pulsed external-cavity quantum cascade laser (ECQCL) with a repetition rate of 600kHz. Optimal wavelength selection for high-temperature combustion gases was first determined by a spectral survey at 1000K near the peak of the absorption band (878cm?1 to 892cm?1) using the ECQCL. Absorption cross section measurements of iC4H8 at 881.4cm?1, the selected high-temperature wavelength, were then conducted from 800K to 1800K behind reflected shocks to characterize temperature dependence at modest pressures (48atm). The species-specific technique was subsequently demonstrated by time-resolved (100kHz) measurements of iso-butene decay during thermal decomposition (12801480K). First-ever shock tube measurements of iC4H8 yields from iso-octane pyrolysis (10701300K) were also produced, with a detection limit of ?100ppm. Experimental results were compared to recent kinetic models to illustrate the potential of this diagnostic for analyzing combustion chemistry.

R.M. Spearrin; S. Li; D.F. Davidson; J.B. Jeffries; R.K. Hanson

2014-01-01T23:59:59.000Z

145

Integrated Kinetic Simulation of Laser-Plasma Interactions, Fast-Electron Generation and Transport in Fast Ignition  

SciTech Connect (OSTI)

We present new results on the physics of short-pulse laser-matter interaction of kilojoule-picosecond pulses at full spatial and temporal scale, using a new approach that combines a 3D collisional electromagnetic Particle-in-Cell code with an MHD-hybrid model of high-density plasma. In the latter, collisions damp out plasma waves, and an Ohm's law with electron inertia effects neglected determines the electric field. In addition to yielding orders of magnitude in speed-up while avoiding numerical instabilities, this allows us to model the whole problem in a single unified framework: the laser-plasma interaction at sub-critical densities, energy deposition at relativistic critical densities, and fast-electron transport in solid densities. Key questions such as the multi-picosecond temporal evolution of the laser energy conversion into hot electrons, the impact of return currents on the laser-plasma interaction, and the effect of self-generated electric and magnetic fields on electron transport will be addressed. We will report applications to current experiments.

Kemp, A; Cohen, B; Divol, L

2009-11-16T23:59:59.000Z

146

Laser-Matter Interaction Above the Plasma Ignition Threshold Intensity  

Science Journals Connector (OSTI)

In this chapter we present the process of laser-matter interaction above the plasma ignition threshold intensity. The physics of the pulsed laser ablation process at high intensities is very complex since it invo...

Mihai Stafe; Aurelian Marcu; Niculae N. Puscas

2014-01-01T23:59:59.000Z

147

Laser Microsurgery in Caenorhabditis elegans Christopher Fang-Yen*  

E-Print Network [OSTI]

CHAPTER 6 Laser Microsurgery in Caenorhabditis elegans Christopher Fang-Yen* , Christopher V. Identifying Cells in C. elegans III. Laser Ablation Theory and Apparatus A. Tissue Damage by Nanosecond and Femtosecond Lasers B. The Laser Apparatus IV. Laser Killing of Cells A. Procedures B. Experimental Design

Fang-Yen, Christopher

148

Performance and Controllability of Pulsed Ion Beam Ablation Propulsion  

SciTech Connect (OSTI)

We propose novel propulsion driven by ablation plasma pressures produced by the irradiation of pulsed ion beams onto a propellant. The ion beam ablation propulsion demonstrates by a thin foil (50 {mu}mt), and the flyer velocity of 7.7 km/s at the ion beam energy density of 2 kJ/cm2 adopted by using the Time-of-flight method is observed numerically and experimentally. We estimate the performance of the ion beam ablation propulsion as specific impulse of 3600 s and impulse bit density of 1700 Ns/m2 obtained from the demonstration results. In the numerical analysis, a one-dimensional hydrodynamic model with ion beam energy depositions is used. The control of the ion beam kinetic energy is only improvement of the performance but also propellant consumption. The spacecraft driven by the ion beam ablation provides high performance efficiency with short-pulsed ion beam irradiation. The numerical results of the advanced model explained latent heat and real gas equation of state agreed well with experimental ones over a wide range of the incident ion beam energy density.

Yazawa, Masaru; Buttapeng, Chainarong; Harada, Nobuhiro [Nagaoka University of Technology, Department of Electrical Engineering, 1603-1 Kamitomioka, Nagaoka, Niigata 940-2188 (Japan); Suematsu, Hisayuki; Jiang Weihua; Yatsui, Kiyoshi [Nagaoka University of Technology, Extreme Energy-Density Research Institute, 1603-1 Kamitomioka, Nagaoka, Niigata 940-2188 (Japan)

2006-05-02T23:59:59.000Z

149

A Mass Spectrometry Study of Isotope Separation in the Laser Plume  

E-Print Network [OSTI]

1.4.2 Atomic Absorption5.3.2 Atomic Absorption Spectrometry . . . . . . . . . . .ablation and diode laser-atomic absorption spectrometry,

Suen, Timothy Wu

2012-01-01T23:59:59.000Z

150

Digital multimirror devices for precision laser micromachining  

E-Print Network [OSTI]

DMD LIFT results 24 PMMA donors New 3D printing technology! BiTe semiconductor film New laser 3D printing facility...An ORC breakthrough 75 µm #12;Summary · DMDs are very useful for precise ablation

151

LaserMatter Interaction in LIBS Experiments  

Science Journals Connector (OSTI)

Clearly, LIBS is only a tiny fraction of all the application domains in which these physical mechanisms have found useful applications. From laser ablation to nuclear fusion, from welding and drilling to surface ...

Andrea Marco Malvezzi

2014-01-01T23:59:59.000Z

152

Laser-induced fluorescence measurements and kinetic analysis of Si atom formation in a rotating disk chemical vapor deposition reactor  

SciTech Connect (OSTI)

An extensive set of laser-induced fluorescence (LIF) measurements of Si atoms during the chemical vapor deposition (CVD) of silicon from silane and disilane in a research rotating disk reactor are presented. The experimental results are compared in detail with predictions from a numerical model of CVD from silane and disilane that treats the fluid flow coupled to gas-phase and gas-surface chemistry. The comparisons showed that the unimolecular decomposition of SiH[sub 2] could not account for the observed gas-phase Si atom density profiles. The H[sub 3]SiSiH [leftrightarrow] Si + SiH[sub 4] and H[sub 3]SiSiH + SiH[sub 2] [leftrightarrow] Si + Si[sub 2]H[sub 6] reactions are proposed as the primary Si atom production routes. The model is in good agreement with the measured shapes of the Si atom profiles and the trends in Si atom density with susceptor temperature, pressure, and reactant gas mixture. 33 refs., 12 figs., 3 tabs.

Ho, P.; Coltrin, M.E.; Breiland, W.G. (Sandia National Lab., Albuquerque, NM (United States))

1994-10-06T23:59:59.000Z

153

Preliminary design and estimate of capital and operating costs for a production scale application of laser decontamination technology  

SciTech Connect (OSTI)

The application of laser ablation technology to the decontamination of radioactive metals, particularly the surfaces of equipment, is discussed. Included is information related to the design, capital and operating costs, and effectiveness of laser ablation technology, based on commercial excimer and Nd:YAG lasers, for the decontamination of production scale equipment.

Pang, Ho-ming; Edelson, M.C.

1994-08-06T23:59:59.000Z

154

Implosion Experiments using Glass Ablators for Direct-Drive Inertial Confinement Fusion V. A. Smalyuk, R. Betti,* J. A. Delettrez, V. Yu. Glebov, D. D. Meyerhofer,* P. B. Radha, S. P. Regan, T. C. Sangster,  

E-Print Network [OSTI]

with overlapped laser beams. To ignite DT fuel on the National Ignition Facility (NIF) [2] with a laser energy. Sangster, J. Sanz, W. Seka, C. Stoeckl, and B. Yaakobi Laboratory for Laser Energetics, University-thick glass shells were conducted on the Omega Laser Facility to test the performance of high-Z glass ablators

155

Spectroscopic diagnostics for ablation cloud of tracer-encapsulated solid pellet in LHD  

SciTech Connect (OSTI)

In the Large Helical Device (LHD), various spectroscopic diagnostics have been applied to study the ablation process of an advanced impurity pellet, tracer-encapsulated solid pellet (TESPEL). The total light emission from the ablation cloud of TESPEL is measured by photomultipliers equipped with individual interference filters, which provide information about the TESPEL penetration depth. The spectra emitted from the TESPEL ablation cloud are measured with a 250 mm Czerny-Turner spectrometer equipped with an intensified charge coupled device detector, which is operated in the fast kinetic mode. This diagnostic allows us to evaluate the temporal evolution of the electron density in the TESPEL ablation cloud. In order to gain information about the spatial distribution of the cloud parameters, a nine image optical system that can simultaneously acquire nine images of the TESPEL ablation cloud has recently been developed. Several images of the TESPEL ablation cloud in different spectral domains will give us the spatial distribution of the TESPEL cloud density and temperature.

Tamura, N.; Kalinina, D. V.; Sato, K.; Sudo, S. [National Institute for Fusion Science, 322-6, Oroshi-cho, Toki-City, Gifu 509-5292 (Japan); Sergeev, V. Yu.; Miroshnikov, I. V.; Sharov, I. A.; Bakhareva, O. A.; Ivanova, D. M.; Timokhin, V. M. [State Polytechnical University, Politechnicheskaya 29, St. Petersburg 195251 (Russian Federation); Kuteev, B. V. [Nuclear Fusion Institute, RRC 'Kurchatov Institute', Kurchatov square 1, Moscow 123182 (Russian Federation)

2008-10-15T23:59:59.000Z

156

BBGKY kinetic approach for an e{sup -}e{sup +}{gamma} plasma created from the vacuum in a strong laser-generated electric field: The one-photon annihilation channel  

SciTech Connect (OSTI)

In the present work a closed system of kinetic equations is obtained from the truncation of the Bogoliubov-Born-Green-Kirkwood-Yvon hierarchy for the description of the vacuum creation of an electron-positron plasma and secondary photons due to a strong laser field. This truncation is performed in the Markovian approximation for the one-photon annihilation channel which is accessible due to the presence of the strong external field. Estimates of the photon production rate are obtained for different domains of laser field parameters (frequency {nu} and field strength E). A huge quantity of optical photons of the quasiclassical laser field is necessary to satisfy the conservation laws of the energy and momentum of the constituents (e{sup -}, e{sup +} and {gamma}) in this channel. Since the number of these optical photons corresponds to the order of perturbation theory, a vanishingly small photon production rate results for the optical region and strongly subcritical fields E<laser photons is small and the production rate of photons from the one-photon annihilation process becomes accessible to observations for subcritical fields E < or approx. E{sub c}. In the infrared region the photon distribution has a 1/k spectrum typical for flicker noise.

Blaschke, D. B. [Institute for Theoretical Physics, University of Wroclaw, 50-204 Wroclaw (Poland); Bogoliubov Laboratory for Theoretical Physics, Joint Institute for Nuclear Research, RU - 141980 Dubna (Russian Federation); Dmitriev, V. V.; Smolyansky, S. A. [Department of Physics, Saratov State University, RU - 410026 Saratov (Russian Federation); Roepke, G. [Institut fuer Physik, University of Rostock, D - 18051 Rostock (Germany)

2011-10-15T23:59:59.000Z

157

Beam current controller for laser ion source  

DOE Patents [OSTI]

The present invention relates to the design and use of an ion source with a rapid beam current controller for experimental and medicinal purposes. More particularly, the present invention relates to the design and use of a laser ion source with a magnetic field applied to confine a plasma flux caused by laser ablation.

Okamura, Masahiro

2014-10-28T23:59:59.000Z

158

Laser-matter Interaction with Submerged Samples  

SciTech Connect (OSTI)

With the long-term goal in mind of investigating if one could possibly design a 'universal solid-sample comminution technique' for debris and rubble, we have studied pulsed-laser ablation of solid samples that were contained within a surrounding fluid. Using pulses with fluences between 2 J and 0.3 J, wavelengths of 351 and 527 nm, and samples of rock, concrete, and red brick, each submerged in water, we have observed conditions in which {micro}m-scale particles can be preferentially generated in a controlled manner, during the laser ablation process. Others have studied laser peening of metals, where their attention has been to the substrate. Our study uses non-metallic substrates and analyzes the particles that are ablated from the process. The immediate impact of our investigation is that laser-comminution portion of a new systems concept for chemical analysis has been verified as feasible.

Mariella, R; Rubenchik, A; Norton, M; Donohue, G; Roberts, K

2010-03-25T23:59:59.000Z

159

Excimer-laser surface treatment of metals for improved adhesion  

Science Journals Connector (OSTI)

Excimer-laser-induced ablation has been used to produce surface structuring of various metals. Such structuring contributed to a 515% enhancement of the bonding strength of these...

Henari, Fryad; Blau, Werner

1995-01-01T23:59:59.000Z

160

Ultrashort-pulse laser generated nanoparticles of energetic materials  

DOE Patents [OSTI]

A process for generating nanoscale particles of energetic materials, such as explosive materials, using ultrashort-pulse laser irradiation. The use of ultrashort laser pulses in embodiments of this invention enables one to generate particles by laser ablation that retain the chemical identity of the starting material while avoiding ignition, deflagration, and detonation of the explosive material.

Welle, Eric J. (Niceville, NM); Tappan, Alexander S. (Albuquerque, NM); Palmer, Jeremy A. (Albuquerque, NM)

2010-08-03T23:59:59.000Z

Note: This page contains sample records for the topic "kinetics laser ablation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

The Center for Laser Applications "An accomplished Center of Excellence"  

E-Print Network [OSTI]

Modular Microfluidic Systems for Drug Discovery Laser-Induced Ignition Studies of Solid Aluminum ParticlesThe Center for Laser Applications "An accomplished Center of Excellence" University of Tennessee and Combined Recovery Factor for High-Temperature Probe, AEDC TASK 09-02 Modeling of the Micro Laser Ablation

Davis, Lloyd M.

162

Laser-direct-driven quasi-isentropic experiments on aluminum  

SciTech Connect (OSTI)

Laser-direct-driven ramp compression experiments were performed on long temporally shaped laser pulses based on an analytical isentropic compression model. Upper pressure limits, the ablation pressure scaling law, and stress-density curves were studied. The validity of the analytical model used, the ablation pressure scaling law, and the phenomena of missing line-imaging velocity interferometer (VISAR) fringes in the experimental results are discussed.

Xue, Quanxi, E-mail: quanxixue@163.com [Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900 (China); State Key Laboratory of Laser Interaction with Matter, Northwest Institute of Nuclear Technology, Xi'an 710024 (China); Wang, Zhebin; Jiang, Shaoen, E-mail: jiangshn@vip.sina.com; Wang, Feng [Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900 (China); Ye, Xisheng; Liu, Jingru [State Key Laboratory of Laser Interaction with Matter, Northwest Institute of Nuclear Technology, Xi'an 710024 (China)

2014-07-15T23:59:59.000Z

163

Method of defining features on materials with a femtosecond laser  

DOE Patents [OSTI]

The invention relates to a pulsed laser ablation method of metals and/or dielectric films from the surface of a wafer, printed circuit board or a hybrid substrate. By utilizing a high-energy ultra-short pulses of laser light, such a method can be used to manufacture electronic circuits and/or electro-mechanical assemblies without affecting the material adjacent to the ablation zone.

Roos, Edward Victor (Los Altos, CA); Roeske, Franklin (Livermore, CA); Lee, Ronald S. (Livermore, CA); Benterou, Jerry J. (Livermore, CA)

2006-05-23T23:59:59.000Z

164

Simple model for ablative stabilization  

Science Journals Connector (OSTI)

We present a simple analytic model for ablative stablization of the Rayleigh-Taylor instability. In this model the effect of ablation is to move the peak of the perturbations to the location of peak pressure. This mechanism enhances the density-gradient stabilization, which is effective at short wavelengths, and it also enhances the stabilization of long-wavelength perturbations due to finite shell thickness. We consider the following density profile: exponential blowoff plasma with a density gradient ?, followed by a constant-density shell of thickness ?t. For perturbations of arbitrary wave number k, we present an explicit expression for the growth rate ? as a function of k, ?, and ?t. We find that thick shells defined by ? ?t?1 have ?2?0 for any k, while thin shells defined by ? ?t<1 can have ?2<0 for small k, reflecting stability by proximity to the back side of the shell. We also present lasnex simulations that are in good agreement with our analytic formulas.

Karnig O. Mikaelian

1992-11-15T23:59:59.000Z

165

Damage and ablation thresholds of fused-silica in femtosecond regime  

SciTech Connect (OSTI)

We present an experimental and numerical study of the damage and ablation thresholds at the surface of a dielectric material, e.g., fused silica, using short pulses ranging from 7 to 300 fs. The relevant numerical criteria of damage and ablation thresholds are proposed consistently with experimental observations of the laser irradiated zone. These criteria are based on lattice thermal melting and electronic cohesion temperature, respectively. The importance of the three major absorption channels (multi-photon absorption, tunnel effect, and impact ionization) is investigated as a function of pulse duration (7-300 fs). Although the relative importance of the impact ionization process increases with the pulse duration, our results show that it plays a role even at short pulse duration (<50 fs). For few optical cycle pulses (7 fs), it is also shown that both damage and ablation fluence thresholds tend to coincide due to the sharp increase of the free electron density. This electron-driven ablation regime is of primary interest for thermal-free laser-matter interaction and therefore for the development of high quality micromachining processes.

Chimier, B.; Uteza, O.; Sanner, N.; Sentis, M. [Laboratoire LP3, UMR 6182 CNRS - Universite de la Mediterranee, C. 917, 163, Av. de Luminy, 13288 Marseille cedex 9 (France); Itina, T. [Laboratoire Hubert Curien - LaHC, UMR 5516 CNRS - Universite Jean Monnet, Bat. F, 18, rue Professeur B. Lauras, 42000 Saint-Etienne (France); Lassonde, P.; Legare, F.; Vidal, F.; Kieffer, J. C. [INRS, Energie, Materiaux et Telecommunications, 1650 bld Lionel Boulet, Varennes (Quebec), J3X 1S2 (Canada)

2011-09-01T23:59:59.000Z

166

Laser-based characterization and decontamination of contaminated facilities  

SciTech Connect (OSTI)

This study examines the application of laser ablation to the characterization and decontamination of painted and unpainted concrete and metal surfaces that are typical of many facilities within the US Department of Energy complex. The utility of this promising technology is reviewed and the essential requirements for efficient ablation extracted. Recent data obtained on the ablation of painted steel surfaces and concrete are presented. The affects of beam irradiance, ablation speed and efficiency, and characteristics of the aerosol effluent are discussed. Characterization of the ablated components of the surface offers the ability of concurrent determination of the level of contamination. This concept can be applied online where the ablation endpoint can be determined. A conceptual system for the characterization and decontamination of surfaces is proposed.

Leong, K.H.; Hunter, B.V.; Grace, J.E.; Pellin, M.J. [Argonne National Lab., IL (United States); Leidich, H.F.; Kugler, T.R. [Lumonics Corp., Livonia, MI (United States)

1996-12-31T23:59:59.000Z

167

Review of multi-dimensional large-scale kinetic simulation and physics validation of ion acceleration in relativistic laser-matter interaction  

SciTech Connect (OSTI)

Two new experimental technologies enabled realization of Break-out afterburner (BOA) - High quality Trident laser and free-standing C nm-targets. VPIC is an powerful tool for fundamental research of relativistic laser-matter interaction. Predictions from VPIC are validated - Novel BOA and Solitary ion acceleration mechanisms. VPIC is a fully explicit Particle In Cell (PIC) code: models plasma as billions of macro-particles moving on a computational mesh. VPIC particle advance (which typically dominates computation) has been optimized extensively for many different supercomputers. Laser-driven ions lead to realization promising applications - Ion-based fast ignition; active interrogation, hadron therapy.

Wu, Hui-Chun [Los Alamos National Laboratory; Hegelich, B.M. [Los Alamos National Laboratory; Fernandez, J.C. [Los Alamos National Laboratory; Shah, R.C. [Los Alamos National Laboratory; Palaniyappan, S. [Los Alamos National Laboratory; Jung, D. [Los Alamos National Laboratory; Yin, L [Los Alamos National Laboratory; Albright, B.J. [Los Alamos National Laboratory; Bowers, K. [Guest Scientist of XCP-6; Huang, C. [Los Alamos National Laboratory; Kwan, T.J. [Los Alamos National Laboratory

2012-06-19T23:59:59.000Z

168

Efficient, high-speed ablation of soft tissue with few-microjoule, femtosecond pulse bursts  

E-Print Network [OSTI]

Femtosecond pulses hold great promise for high-precision tissue removal. However, ablation rates are severely limited by the need to keep average laser power low to avoid collateral damage due to heat accumulation. Furthermore, previously reported pulse energies preclude delivery in flexible fibers, hindering in vivo operation. Both of these problems can be addressed through use of groups of high-repetition-rate pulses, or bursts. Here, we report a novel fiber laser and demonstrate ultrafast burst-mode ablation of brain tissue at rates approaching 1 mm$^3$/min, an order of magnitude improvement over previous reports. Burst mode operation is shown to be superior in terms of energy required and avoidance of thermal effects, compared to uniform repetition rates. These results can pave the way to in vivo operation at medically relevant speeds, delivered via flexible fibers to surgically hard-to-reach targets, or with simultaneous magnetic resonance imaging.

Kerse, Can; Kalayc?o?lu, Hamit; A??k, Mehmet D; Akaalan, nder; Ilday, F mer

2014-01-01T23:59:59.000Z

169

Manufacturing of Er:ZBLAN ridge waveguides by pulsed laser deposition and ultrafast laser micromachining for green integrated lasers  

Science Journals Connector (OSTI)

Laser radiation is used both for the deposition of the laser active thin films and for the microstructuring to define wave guiding structures for the fabrication of waveguide lasers. Thin films of Er:ZBLAN (a fluoride glass consisting of ZrF4, BaF2, LaF3, AlF3, NaF, ErF3) for green up-conversion lasers (545nm) are produced by pulsed laser deposition using ArF excimer laser radiation (wavelength 193nm). Manufacturing of the laser active waveguides by microstructuring is done using fs-laser ablation of the deposited films. The structural and optical properties of the films and the damping losses of the structured waveguides are determined in view of the design and the fabrication of compact and efficient diode pumped waveguide lasers. The resulting waveguides are polished, provided with resonator mirrors, pumped using diode lasers and characterized.

Jens Gottmann; Leonid Moiseev; Ion Vasilief; Dirk Wortmann

2008-01-01T23:59:59.000Z

170

Kinetically tailored properties of electron-beam excited XeF(C. -->. A) and XeF(B. -->. X) laser media using an Ar-Kr buffer mixture  

SciTech Connect (OSTI)

Use of a two-component buffer gas comprised of Ar and Kr results in electron-beam excited XeF(C..-->..A) laser pulse energy and intrinsic efficiency values comparable to those of UV rare gas-halide lasers. Herein the authors report measurements of transient absorption confirming that the primary effect of a buffer comprised of Ar and Kr is a significantly lower level of ionized and excited species that absorb in the blue-green spectral region. Spectral analysis of a variety of mixtures show that the Ar-Kr buffer also benefits XeF(C..-->..A) laser performance due to an increase in gain in the 400-450 nm region caused by the presence of the Kr/sub 2/F excimer. In addition, a large increase in absorption at --351 nm, also due to Kr/sub 2/F, suppresses oscillation on the competitive XeF(B..-->..X) transition and, for certain conditions, makes efficient simultaneous oscillation of the XeF(B..-->..X) and XeF(C..-->..A) laser transitions possible.

Nighan, W.L.; Sauerbrey, R.A.; Zhu, Y.; Tittel, F.K.; Wilson, W.L. Jr.

1987-02-01T23:59:59.000Z

171

Laser ion source for Columbia Universitys microbeam A.W. Bigelow a,*, G. Randers-Pehrson a  

E-Print Network [OSTI]

Laser ion source for Columbia University?s microbeam A.W. Bigelow a,*, G. Randers-Pehrson a , R High School, NY, USA Available online 29 August 2005 Abstract A laser ion source that will be installed for irradiation experiments with mammalian cells. Through laser ablation the laser ion source can produce heavy

Brenner, David Jonathan

172

Pathways to Inertial Fusion Energy Laser Direct Drive  

E-Print Network [OSTI]

(NRL) Smoothing by Spectral Dispersion ­ SSD (LLE) DT ice preheated ablator (lower density) DT ice "Gain" = Fusion power OUT / laser power IN 143/572 = 25% Recirculating power (Nuclear reactions (electricity) Target "Gain" = Fusion power OUT / laser power IN 143/880 = 16% Recirculating power (Nuclear

173

ZnO nano-rods synthesized by nano-particle-assisted pulsed-laser deposition  

Science Journals Connector (OSTI)

We succeeded in synthesizing ZnO nanorods by nanoparticle assisted pulsed-laser deposition (PLD) without using any catalyst where nanoparticles formed by condensation of ablated particles play an important rol...

T. Okada; B.H. Agung; Y. Nakata

2004-09-01T23:59:59.000Z

174

Laser Roadshow  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

outreach Laser Roadshow The NIF Laser Roadshow includes a number of interactive laser demonstrations (Laser Light Fountain, Laser DJ, and NIF "3D ride") that have traveled across...

175

Phase transformation and crystallization kinetics of a-Ge/Cu bilayer for blue-ray recording under thermal annealing and pulsed laser irradiation  

SciTech Connect (OSTI)

Similar phase formation and crystallization behaviors have been observed in the a-Ge/Cu bilayer under thermal annealing and pulsed laser irradiation. The Cu{sub 3}Ge phase would form prior to the crystallization of a-Ge. The crystallization temperature and activation energy for crystallization of a-Ge were reduced to 310 deg. C and 2.75 eV, respectively, due to the fast Ge diffusion in the already formed germanide phases. The reaction exponent m of {approx}2.0 for the a-Ge/Cu bilayer corresponds to a crystallization process in which grain growth occurs with nucleation, and the nucleation rate decreases with the progress of the grain growth process. Under pulsed laser irradiation, the maximum data-transfer-rates of 44, 56, 74, and 112 Mbit/s can be achieved in the write-once blue-ray disk at the recording powers of 3, 4, 5, and 6 mW, respectively. The a-Ge/Cu bilayer also demonstrated sufficient optical contrast and adequate absorptance for low power and high speed write-once blue-ray recording.

Her, Yung-Chiun; Tu, Wei-Ting; Tsai, Ming-Hsin [Department of Materials Science and Engineering, National Chung Hsing University, Taichung, Taiwan 40254 (China)

2012-02-15T23:59:59.000Z

176

Apparatus for the laser ablative synthesis of carbon nanotubes  

DOE Patents [OSTI]

An RF-induction heated side-pumped synthesis chamber for the production of carbon nanotubes. Such an apparatus, while capable of producing large volumes of carbon nanotubes, concurrently provides a simplified apparatus that allows for greatly reduced heat up and cool down times and flexible flowpaths that can be readily modified for production efficiency optimization.

Smith, Michael W. (Newport News, VA); Jordan, Kevin (Newport News, VA)

2010-02-16T23:59:59.000Z

177

Generation of Core/shell Nanoparticles with Laser Ablation  

E-Print Network [OSTI]

.............................................15 Figure 6. Zn/glass CS-NP. (a), (c) HRTEM image of Zn/glass CS-NP. The Zn region is darker than the glass (SiO2) region due to its higher atomic weight, (b), (d) EDS line profile of Zn/glass CS-NP. The maximum Zn signal appears at the center... Page Figure 7. Sn/glass CS-NP. (a) HRTEM image of a Sn/glass CS-NP. The Sn region is darker than the glass (SiO2) region in the HDRTEM images due to its higher atomic weight, (b) EDS line profile of the Sn/glass CS-NP. The maximum Sn signal appears...

Jo, Young Kyong

2012-10-19T23:59:59.000Z

178

Improvements to Laser Ablation-Inductively Coupled Plasma-Mass...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

for trace elemental analysis of solids. Trace element composition can be useful in forensic applications for matching or attribution studies, in which a material recovered from...

179

Synthesis of materials with infrared and ultraviolet lasers  

SciTech Connect (OSTI)

This paper discusses three divergent examples of synthesis of materials with lasers. The three techniques are: (1) infrared (CO/sub 2/) laser synthesis of silane (SiH/sub 4/) from disilane (Si/sub 2/H/sub 6/); (2) excimer (ArF) laser production of fine silicon powders from methyl- and chloro-substituted silanes; and, (3) excimer (KrF) laser production of fine metallic powders by laser ablation. The mechanism for each process is discussed along with some conclusions about the features of the laser radiation that enable each application. 19 refs., 12 figs., 2 tabs.

Lyman, J.L.

1988-01-01T23:59:59.000Z

180

Measurements of fuel and ablator R in Symmetry-Capsule implosions with the Magnetic Recoil neutron Spectrometer (MRS) on the National Ignition Facilitya)  

E-Print Network [OSTI]

Lawrence Livermore National Laboratory, Livermore, California 94550, USA 3 Laboratory for Laser Energetics Spectrometer (MRS) on the National Ignition Facility (NIF) measures the neutron spectrum in the energy range-filled symmetry-capsule implosions at the NIF. DT-fuel R's of 80­140 mg/cm2 and CH-ablator R's of 400­680 mg/cm2

Note: This page contains sample records for the topic "kinetics laser ablation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

Early stage expansion and time-resolved spectral emission of laser-induced  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Early stage expansion and time-resolved spectral emission of laser-induced Early stage expansion and time-resolved spectral emission of laser-induced plasma from polymer Title Early stage expansion and time-resolved spectral emission of laser-induced plasma from polymer Publication Type Journal Article Year of Publication 2009 Authors Boueri, Myriam, Matthieu Baudelet, Jin Yu, Xianglei Mao, Samuel S. Mao, and Richard E. Russo Journal Applied Surface Science Volume 255 Issue 24 Pagination 9566-9571 Date Published 09/2009 Keywords Early stage plasma expansion, Laser ablation of polymer, Plasma spectral emission Abstract In the nanosecond laser ablation regime, absorption of laser energy by the plasma during its early stage expansion critically influences the properties of the plasma and thus its interaction with ambient air. These influences can significantly alter spectral emission of the plasma. For organic samples especially, recombination of the plasma with the ambient air leads to interfering emissions with respect to emissions due to native species evaporated from the sample. Distinguishing interfering emissions due to ambient air represents a critical issue for the application of laser-induced breakdown spectroscopy (LIBS) to the analysis of organic materials. In this paper, we report observations of early stage expansion and interaction with ambient air of the plasma induced on a typical organic sample (nylon) using timeresolved shadowgraph. We compare, in the nanosecond ablation regime, plasmas induced by infrared (IR) laser pulses (1064 nanometers) and ultraviolet (UV) laser pulses (266 nanometers). Nanosecond ablation is compared with femtosecond ablation where the post-ablation interaction is absent. Subsequent to the early stage expansion, we observe for each studied ablation regime, spectral emission from CN, a typical radical for organic and biological samples. Time-resolved LIBS allows identifying emissions from native molecular species and those due to recombination with ambient air through their different time evolution behaviors.

182

Laser Ignition  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Laser Ignition Laser Ignition A first excitation laser or other excitation light source is used in tandem with an ignitor laser to provide a compact, durable, engine deployable...

183

Kinetic studies of isoprene reactions with hydroxyl and chlorine radicals  

E-Print Network [OSTI]

Kinetic studies of the isoprene oxidation reactions initiated by the hydroxyl radical OH and the chlorine atom Cl have been investigated using a fast-flow reactor in conjunction with chemical ionization mass spectrometry (CIMS) and using laser...

Suh, Inseon

2012-06-07T23:59:59.000Z

184

Design Calculations For NIF Convergent Ablator Experiments  

SciTech Connect (OSTI)

The NIF convergent ablation tuning effort is underway. In the early experiments, we have discovered that the design code simulations over-predict the capsule implosion velocity and shock flash rhor, but under-predict the hohlraum x-ray flux measurements. The apparent inconsistency between the x-ray flux and radiography data implies that there are important unexplained aspects of the hohlraum and/or capsule behavior.

Olson, R E; Hicks, D G; Meezan, N B; Callahan, D A; Landen, O L; Jones, O S; Langer, S H; Kline, J L; Wilson, D C; Rinderknecht, H; Zylstra, A; Petrasso, R D

2011-10-25T23:59:59.000Z

185

Gain spectra and temperature characteristics of quantum cascade lasers  

Science Journals Connector (OSTI)

We have developed a theory describing the operation of lasers based on intersubband transitions in a quantum well. The theory combines a first-principles description of the intersubband lineshape and the optical gain with kinetic models for carrier heating. ... Keywords: carrier heating, gain spectra, intersubband lineshape, intersubband transitions, kinetic models, laser theory, optical gain, quantum cascade lasers, quantum well, quantum well lasers, room-temperature high-power operation, temperature characteristics

V. Gorfinkel; S. Luryi; B. Gelmont

1995-11-01T23:59:59.000Z

186

Laser surface cleaning  

SciTech Connect (OSTI)

The objective of this work is a laboratory demonstration that red-lead primer and two-part epoxy paints can be stripped from concrete and metal surfaces using surface cleaning systems based on pulsed-repetition CO{sub 2} lasers. The three goals are to: (1) demonstrate coatings removal, including surface pore cleaning; (2) demonstrate that there is negligible release of ablated contaminants to the environment; and (3) demonstrate that the process will generate negligible amounts of additional waste compared to competing technologies. Phase 1 involved site visits to RMI and Fernald to assess the cleaning issues for buildings and parts. In addition, Phase 1 included detailed designs of a more powerful system for industrial cleaning rates, including laser, articulating optics, ablated-material capture suction nozzle attached to a horizontal raster scanner for floor cleaning, and filtration system. Some concept development is also being done for using robots, and for parts cleaning. In Phase 2 a transportable 6 kW system will be built and tested, with a horizontal surface scanner for cleaning paint from floors. The laboratory tests will again be instrumented. Some concept development will continue for using robots, and for parts cleaning. This report describes Phase 1 results.

Freiwald, J.G.; Freiwald, D.A.

1994-12-31T23:59:59.000Z

187

Ion Acceleration by Short Chirped Laser Pulses  

E-Print Network [OSTI]

Direct laser acceleration of ions by short frequency-chirped laser pulses is investigated theoretically. We demonstrate that intense beams of ions with a kinetic energy broadening of about 1 % can be generated. The chirping of the laser pulse allows the particles to gain kinetic energies of hundreds of MeVs, which is required for hadron cancer therapy, from pulses of energies of the order of 100 J. It is shown that few-cycle chirped pulses can accelerate ions more efficiently than long ones, i.e. higher ion kinetic energies are reached with the same amount of total electromagnetic pulse energy.

Li, Jian-Xing; Keitel, Christoph H; Harman, Zoltn

2015-01-01T23:59:59.000Z

188

Trace element fingerprinting of ancient Chinese gold with femtosecond laser  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Trace element fingerprinting of ancient Chinese gold with femtosecond laser Trace element fingerprinting of ancient Chinese gold with femtosecond laser ablation-inductivity coupled mass spectrometry Title Trace element fingerprinting of ancient Chinese gold with femtosecond laser ablation-inductivity coupled mass spectrometry Publication Type Journal Article Year of Publication 2009 Authors Brostoff, Lynn B., Jhanis J. Gonzalez, Paul Jett, and Richard E. Russo Journal Journal of Archeological Science Volume 36 Start Page 461 Issue 2 Pagination 461-466 Date Published 02/2009 Keywords Ancient gold, femtosecond, la-icp-ms, Trace element Abstract In this collaborative investigation, femtosecond laser ablation-inductively coupled mass spectrometry (LA-ICP-MS) was applied to the study of a remarkable group of ancient Chinese gold objects in the Smithsonian's Freer Gallery of Art and Arthur M. Sackler Gallery. Taking advantage of the superior ablation characteristics and high precision of a femtosecond 266 nm Ti:sapphire laser at Lawrence Berkeley National Laboratory, major, minor and trace element concentrations in the gold fragments were quantified. Results validate use of femtosecond LA-ICP-MS for revealing ''fingerprints'' in minute gold samples. These fingerprints allow us to establish patterns based on the association of silver, palladium and platinum that support historical, technical and stylistic relationships, and shed new light on these ancient objects.

189

Design of a deuterium and tritium-ablator shock ignition target for the National Ignition Facility  

SciTech Connect (OSTI)

Shock ignition presents a viable path to ignition and high gain on the National Ignition Facility (NIF). In this paper, we describe the development of the 1D design of 0.5 MJ class, all-deuterium and tritium (fuel and ablator) shock ignition target that should be reasonably robust to Rayleigh-Taylor fluid instabilities, mistiming, and hot electron preheat. The target assumes 'day one' NIF hardware and produces a yield of 31 MJ with reasonable allowances for laser backscatter, absorption efficiency, and polar drive power variation. The energetics of polar drive laser absorption require a beam configuration with half of the NIF quads dedicated to launching the ignitor shock, while the remaining quads drive the target compression. Hydrodynamic scaling of the target suggests that gains of 75 and yields 70 MJ may be possible.

Terry, Matthew R.; Perkins, L. John; Sepke, Scott M. [Lawrence Livermore National Laboratory, 7000 East Ave., Livermore, California 94550 (United States)

2012-11-15T23:59:59.000Z

190

CT-guided Bipolar and Multipolar Radiofrequency Ablation (RF Ablation) of Renal Cell Carcinoma: Specific Technical Aspects and Clinical Results  

SciTech Connect (OSTI)

Purpose. This study was designed to evaluate the clinical efficacy of CT-guided bipolar and multipolar radiofrequency ablation (RF ablation) of renal cell carcinoma (RCC) and to analyze specific technical aspects between both technologies. Methods. We included 22 consecutive patients (3 women; age 74.2 {+-} 8.6 years) after 28 CT-guided bipolar or multipolar RF ablations of 28 RCCs (diameter 2.5 {+-} 0.8 cm). Procedures were performed with a commercially available RF system (Celon AG Olympus, Berlin, Germany). Technical aspects of RF ablation procedures (ablation mode [bipolar or multipolar], number of applicators and ablation cycles, overall ablation time and deployed energy, and technical success rate) were analyzed. Clinical results (local recurrence-free survival and local tumor control rate, renal function [glomerular filtration rate (GFR)]) and complication rates were evaluated. Results. Bipolar RF ablation was performed in 12 procedures and multipolar RF ablation in 16 procedures (2 applicators in 14 procedures and 3 applicators in 2 procedures). One ablation cycle was performed in 15 procedures and two ablation cycles in 13 procedures. Overall ablation time and deployed energy were 35.0 {+-} 13.6 min and 43.7 {+-} 17.9 kJ. Technical success rate was 100 %. Major and minor complication rates were 4 and 14 %. At an imaging follow-up of 15.2 {+-} 8.8 months, local recurrence-free survival was 14.4 {+-} 8.8 months and local tumor control rate was 93 %. GFR did not deteriorate after RF ablation (50.8 {+-} 16.6 ml/min/1.73 m{sup 2} before RF ablation vs. 47.2 {+-} 11.9 ml/min/1.73 m{sup 2} after RF ablation; not significant). Conclusions. CT-guided bipolar and multipolar RF ablation of RCC has a high rate of clinical success and low complication rates. At short-term follow-up, clinical efficacy is high without deterioration of the renal function.

Sommer, C. M., E-mail: christof.sommer@med.uni-heidelberg.de [University Hospital Heidelberg, INF 110, Department of Diagnostic and Interventional Radiology (Germany); Lemm, G.; Hohenstein, E. [Minimally Invasive Therapies and Nuclear Medicine, SLK Kliniken Heilbronn GmbH, Clinic for Radiology (Germany); Bellemann, N.; Stampfl, U. [University Hospital Heidelberg, INF 110, Department of Diagnostic and Interventional Radiology (Germany); Goezen, A. S.; Rassweiler, J. [Clinic for Urology, SLK Kliniken Heilbronn GmbH (Germany); Kauczor, H. U.; Radeleff, B. A. [University Hospital Heidelberg, INF 110, Department of Diagnostic and Interventional Radiology (Germany); Pereira, P. L. [Minimally Invasive Therapies and Nuclear Medicine, SLK Kliniken Heilbronn GmbH, Clinic for Radiology (Germany)

2013-06-15T23:59:59.000Z

191

Emission characteristics and dynamics of C2 from laser produced graphite plasma  

E-Print Network [OSTI]

Emission characteristics and dynamics of C2 from laser produced graphite plasma S. S. Harilal, Riju 1996; accepted for publication 20 December 1996 The emission features of laser ablated graphite plume diagnostic technique. Time resolved optical emission spectroscopy is employed to reveal the velocity

Harilal, S. S.

192

Laser Desorption/Ionization of Transition Metal Atoms and Oxides from Solid Argon Lester Andrews,*, Andreas Rohrbacher, Christopher M. Laperle, and Robert E. Continetti  

E-Print Network [OSTI]

, approximately 10% of the gas sample condensed on the 10K copper plate. For ablation a focused (10 cm f of the laser-ablated metal atoms and O2 in excess argon during condensation at 10 K, have been laser desorbed spectrometry. Adding the C6H5Br chromophore to the Ar/O2 gas mixture also enhanced the metal and oxide ion

Continetti, Robert E.

193

Plasmadynamics and ionization kinetics of thermionic energy conversion  

SciTech Connect (OSTI)

To reduce the plasma arc-drop, thermionic energy conversion is studied with both analytical and numerical tools. Simplifications are made in both the plasmadynamic and ionization-recombination theories. These are applied to a scheme proposed presently using laser irradiation to enhance the ionization kinetics of the thermionic plasma and thereby reduce the arc-drop. It is also predicted that it is possible to generate the required laser light from a thermionic-type cesium plasma. The analysis takes advantage of theoretical simplifications derived for the ionization-recombination kinetics. It is shown that large laser ionization enhancements can occur and that collisional cesium recombination lasing is expected. To complement the kinetic theory, a numerical method is developed to solve the thermionic plasma dynamics. To combine the analysis of ionization-recombination kinetics with the plasma dynamics of thermionic conversion, a finite difference computer program is constructed. It is capable of solving for both unsteady and steady thermionic converter behavior including possible laser ionization enhancement or atomic recombination lasing. A proposal to improve thermionic converter performance using laser radiation is considered. In this proposed scheme, laser radiation impinging on a thermionic plasma enhances the ionization process thereby raising the plasma density and reducing the plasma arc-drop. A source for such radiation may possibly be a cesium recombination laser operating in a different thermionic converter. The possibility of this being an energy efficient process is discussed. (WHK)

Lawless, J.L. Jr.; Lam, S.H.

1982-02-01T23:59:59.000Z

194

Hydrodynamic Efficiency of Ablation Propulsion with Pulsed Ion Beam  

SciTech Connect (OSTI)

This paper presents the hydrodynamic efficiency of ablation plasma produced by pulsed ion beam on the basis of the ion beam-target interaction. We used a one-dimensional hydrodynamic fluid compressible to study the physics involved namely an ablation acceleration behavior and analyzed it as a rocketlike model in order to investigate its hydrodynamic variables for propulsion applications. These variables were estimated by the concept of ablation driven implosion in terms of ablated mass fraction, implosion efficiency, and hydrodynamic energy conversion. Herein, the energy conversion efficiency of 17.5% was achieved. In addition, the results show maximum energy efficiency of the ablation process (ablation efficiency) of 67% meaning the efficiency with which pulsed ion beam energy-ablation plasma conversion. The effects of ion beam energy deposition depth to hydrodynamic efficiency were briefly discussed. Further, an evaluation of propulsive force with high specific impulse of 4000s, total impulse of 34mN and momentum to energy ratio in the range of {mu}N/W was also analyzed.

Buttapeng, Chainarong; Yazawa, Masaru; Harada, Nobuhiro [Department of Electrical Engineering, Nagaoka University of Technology, 1603-1, Kamitomioka, Nagaoka 940-2188 (Japan); Suematsu, Hisayuki; Jiang Weihua; Yatsui, Kiyoshi [Extreme Energy-Density Research Institute, Nagaoka University of Technology, 1603-1, Kamitomioka, Nagaoka 940-2188 (Japan)

2006-05-02T23:59:59.000Z

195

Laser Cladding  

Science Journals Connector (OSTI)

Laser cladding is a surface modification process in which a laser beam is used to melt an addition ... process must be clearly differentiated from that of laser surface alloying ( Laser Surface Al...

Prof. Dr. Jos L. Ocaa; Prof. Janez Grum

2013-01-01T23:59:59.000Z

196

Strongly Inhibited Rayleigh-Taylor Growth with 0.25-?m Lasers  

Science Journals Connector (OSTI)

It is shown through numerical simulation that the Rayleigh-Taylor growth rate for targets accelerated by laser ablation, is reduced below the classical value, (kg)12, by factors of 3-4 with 0.25-?m laser light. The simulation results are supported by an analytical expression for the growth rates. These results provide further evidence for the viability of high-aspect-ratio shells in direct-drive laser fusion.

Mark H. Emery; John H. Gardner; Stephen E. Bodner

1986-08-11T23:59:59.000Z

197

Lasers in Surgery and Medicine 44:805814 (2012) Femtosecond Plasma Mediated Laser Ablation Has  

E-Print Network [OSTI]

of Pediatrics, Radiology, and Microbiology & Immunology, Stanford University School of Medicine, Stanford,4 Christopher H. Contag, PhD,2,5,6? and Derrick C. Wan, MD 1?? 1 Hagey Laboratory for Pediatric Regenerative

Palanker, Daniel

198

T-3 electron-beam-excited laser system  

SciTech Connect (OSTI)

A laser system specifically designed to study the kinetics of electron-beam driven systems is described. Details of the system are given along with measurements of the electron-beam uniformity and deposition in the laser medium. Some HF laser results obtained with this system are also given.

Klein, R A

1981-02-01T23:59:59.000Z

199

A new pulsed laser deposition technique: Scanning multi-component pulsed laser deposition method  

SciTech Connect (OSTI)

The scanning multi-component pulsed laser deposition (PLD) method realizes uniform depositions of desired coatings by a modified pulsed laser deposition process, preferably with a femto-second laser-system. Multi-component coatings (single or multilayered) are thus deposited onto substrates via laser induced ablation of segmented targets. This is achieved via horizontal line-scanning of a focused laser beam over a uniformly moving target's surface. This process allows to deposit the desired composition of the coating simultaneously, starting from the different segments of the target and adjusting the scan line as a function of target geometry. The sequence and thickness of multilayers can easily be adjusted by target architecture and motion, enabling inter/intra layer concentration gradients and thus functional gradient coatings. This new, simple PLD method enables the achievement of uniform, large-area coatings. Case studies were performed with segmented targets containing aluminum, titanium, and niobium. Under the laser irradiation conditions applied, all three metals were uniformly ablated. The elemental composition within the rough coatings obtained was fixed by the scanned area to Ti-Al-Nb = 1:1:1. Crystalline aluminum, titanium, and niobium were found to coexist side by side at room temperature within the substrate, without alloy formation up to 600 deg. C.

Fischer, D.; Jansen, M. [Max Planck Institute for Solid State Research, Heisenbergstrasse 1, 70569 Stuttgart (Germany); Fuente, G. F. de la [Instituto de Ciencia de Materiales de Aragon (CSIC-Universidad de Zaragoza), Maria de Luna, 3, 50018 Zaragoza (Spain)

2012-04-15T23:59:59.000Z

200

Substrate modification by adding ablation of localized complex fractionated electrograms after stepwise linear ablation in persistent atrial fibrillation  

Science Journals Connector (OSTI)

Linear left atrial (LA) ablation in patients with persistent atrial fibrillation (PsAF) resulting in the elimination of most complex fractionated electrogram (CFE) sites has been demonstrated. This study ... desi...

Shiro Nakahara; Tohru Kamijima; Yuichi Hori

2014-03-01T23:59:59.000Z

Note: This page contains sample records for the topic "kinetics laser ablation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

Nonequilibrium quantum kinetics  

SciTech Connect (OSTI)

This paper contains viewgraphs on non-equilibrium quantum kinetics of nuclear reactions at the intermediate and high energy ranges.

Danielewicz, P.

1997-09-22T23:59:59.000Z

202

LLE (Laboratory for Laser Energetics) review  

SciTech Connect (OSTI)

This volume of the LLE Review, covering the period April--June 1990, contains articles in two main sections, Progress in Laser Fusion and Advanced Technology Developments. The first article presents the theoretical interpretation of the glass-ablator cryogenic-implosion experiments recently conducted on OMEGA. It is followed by an article describing the analysis of neutron time-of-flight data taken during DT and DD experiments; and a discussion of the improvements to laser diagnostics that now provide for precise control of the OMEGA laser is given. This paper contains a report on the development of transparent conductive coatings for KDP crystals, and a discussion of the study of the transient-surface Debye-Waller effect in materials irradiated with an ultrafast laser.

Kumpan, S.A. (ed.)

1990-01-01T23:59:59.000Z

203

Infrared absorption spectroscopy and chemical kinetics of free radicals  

SciTech Connect (OSTI)

This research is directed at the detection, monitoring, and study of chemical kinetic behavior by infrared absorption spectroscopy of small free radical species thought to be important intermediates in combustion. During the last year, infrared kinetic spectroscopy using excimer laser flash photolysis and color-center laser probing has been employed to study the high resolution spectrum of HCCN, the rate constant of the reaction between ethynyl (C{sub 2}H) radical and H{sub 2} in the temperature region between 295 and 875 K, and the recombination rate of propargyl (CH{sub 2}CCH) at room temperature.

Curl, R.F.; Glass, G.P. [Rice Univ., Houston, TX (United States)

1993-12-01T23:59:59.000Z

204

Laser Ignition  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Laser Ignition Laser Ignition Laser Ignition A first excitation laser or other excitation light source is used in tandem with an ignitor laser to provide a compact, durable, engine deployable fuel ignition laser system. Available for thumbnail of Feynman Center (505) 665-9090 Email Laser Ignition A first excitation laser or other excitation light source is used in tandem with an ignitor laser to provide a compact, durable, engine deployable fuel ignition laser system. Reliable fuel ignition is provided over a wide range of fuel conditions by using a single remote excitation light source for one or more small lasers located proximate to one or more fuel combustion zones. In two embodiments the beam from the excitation light source is split with a portion of it going to the ignitor laser and a second portion

205

Composition analysis by scanning femtosecond laser ultraprobing (CASFLU).  

DOE Patents [OSTI]

The composition analysis by scanning femtosecond ultraprobing (CASFLU) technology scans a focused train of extremely short-duration, very intense laser pulses across a sample. The partially-ionized plasma ablated by each pulse is spectrometrically analyzed in real time, determining the ablated material's composition. The steering of the scanned beam thus is computer directed to either continue ablative material-removal at the same site or to successively remove nearby material for the same type of composition analysis. This invention has utility in high-speed chemical-elemental, molecular-fragment and isotopic analyses of the microstructure composition of complex objects, e.g., the oxygen isotopic compositions of large populations of single osteons in bone.

Ishikawa, Muriel Y. (Livermore, CA); Wood, Lowell L. (Simi Valley, CA); Campbell, E. Michael (Danveille, CA); Stuart, Brent C. (Livermore, CA); Perry, Michael D. (Livermore, CA)

2002-01-01T23:59:59.000Z

206

E-Print Network 3.0 - atrioventricular node ablation Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Summary: , DVM; G. Allan Johnson, PhD; Margaret L. Kirby, PhD Cardiac neural crest (CNC) ablation in embryonic... -operated and CNC-ablated embryos acquired by magnetic...

207

Impact of left atrial appendage ridge ablation on the complex fractionated electrograms in persistent atrial fibrillation  

Science Journals Connector (OSTI)

High-density left atrial mapping identified continuous CFE sites in 50% and high-DFs ... ablation, LAA ablation significantly increased the mean CFE cycle length from 98??29 to...P?

Shiro Nakahara; Yuichi Hori; Akiko Hayashi

2014-10-01T23:59:59.000Z

208

E-Print Network 3.0 - ablation mass spectroscopy Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

implants into rat livers after radiofrequency ablation were quantified by atomic absorption spectroscopy... Local carboplatin delivery and tissue distribution in...

209

kinetic wave energy  

Science Journals Connector (OSTI)

kinetic wave energy ? kinetische Wellenenergie f [Teil der Wellenlnge, die im Feld der Orbitalgeschwindigkeiten unter der Welle enthalten ist und als Orbitalbewegung am Ort verbleibt

2014-08-01T23:59:59.000Z

210

Quiescence in R3327-G Rat Prostate Tumors after Androgen Ablation  

Science Journals Connector (OSTI)

...quiescence) or supra-additive (reduction in repopulation...8 h before tumor removal. Androgen ablation...quiescence) or supra-additive (reduction in repopulation...8 h before tumor removal. Androgen ablation...quiescence) or supra-additive (reduction in repopulation...8 h before tumor removal. Androgen ablation...

Alan Pollack; Daryl Lim Joon; Catherine S. Wu; Charles Sikes; Masatoshi Hasegawa; Nicholas H. A. Terry; R. Allen White; Gunar K. Zagars; and Marvin L. Meistrich

1997-06-15T23:59:59.000Z

211

Laser Temperature-Jump Spectroscopy of Intrinsically Disordered Proteins  

Science Journals Connector (OSTI)

Laser temperature-jump methods allow an experimenter to study the kinetics and dynamics of very rapid solution-phase processes, including conformational dynamics of biomolecules on time scales of nanoseconds a...

Stephen J. Hagen

2012-01-01T23:59:59.000Z

212

Laser-initiated ignition of hydrogen-air mixtures  

Science Journals Connector (OSTI)

The subject of investigation is the kinetic mechanisms intensifying chain reactions that proceed in a hydrogen-air mixture when O2 molecules dissociate under the action of laser radiation with wavelength ? ...

A. M. Starik; P. S. Kuleshov; N. S. Titova

2009-03-01T23:59:59.000Z

213

A model for self-defocusing in laser drilling of polymeric materials  

SciTech Connect (OSTI)

A numerical thermal model is presented for laser microvias drilling in multilayer electronic substrates with Nd:YAG (YAG denotes yttrium aluminum garnet) and CO{sub 2} lasers. Such substrates have different optical properties such as the refractive index and absorption coefficient at these two laser wavelengths, resulting in different drilling mechanisms. Since the skin depth of the polymer is large for both the lasers, volumetric heating is considered in the model. As soon as a small cavity is formed during the drilling process, the concave curvature of the drilling front acts as a concave lens that diverges the incident laser beam. This self-defocusing effect can greatly reduce the drilling speed as predicted by the model. This effect makes the refractive index of the substrate at different wavelengths an important parameter for laser drilling. The model was used to calculate the laser ablation thresholds which were found to be 8 and 56 J/cm{sup 2} for the CO{sub 2} and Nd:YAG lasers respectively. Due to the expulsion of materials because of high internal pressures in the case of Nd:YAG laser microvia drilling, the ablation threshold may be far below the calculated value. A particular laser beam shape, such as pitch fork, was found to drill better holes than the Gaussian beam.

Zhang Chong; Quick, Nathaniel R.; Kar, Aravinda [Department of Mechanical, Materials and Aerospace Engineering, College of Optics and Photonics, Center for Research and Education in Optics and Lasers (CREOL), University of Central Florida, Orlando, Florida 32816-2700 (United States); AppliCote Associates, LLC, 1445 Dolgner Place, Suite 23, Sanford, Florida 32771 (United States); College of Optics and Photonics, Center for Research and Education in Optics and Lasers (CREOL), University of Central Florida, Orlando, Florida 32816-2700 (United States)

2008-01-01T23:59:59.000Z

214

Experimental investigation of the ribbon-array ablation process  

SciTech Connect (OSTI)

Ablation processes of ribbon-array loads, as well as wire-array loads for comparison, were investigated on Qiangguang-1 accelerator. The ultraviolet framing images indicate that the ribbon-array loads have stable passages of currents, which produce axially uniform ablated plasma. The end-on x-ray framing camera observed the azimuthally modulated distribution of the early ablated ribbon-array plasma and the shrink process of the x-ray radiation region. Magnetic probes measured the total and precursor currents of ribbon-array and wire-array loads, and there exists no evident difference between the precursor currents of the two types of loads. The proportion of the precursor current to the total current is 15% to 20%, and the start time of the precursor current is about 25 ns later than that of the total current. The melting time of the load material is about 16 ns, when the inward drift velocity of the ablated plasma is taken to be 1.5 Multiplication-Sign 10{sup 7} cm/s.

Li Zhenghong; Xu Rongkun; Chu Yanyun; Yang Jianlun; Xu Zeping; Ye Fan; Chen Faxin; Xue Feibiao; Ning Jiamin; Qin Yi; Meng Shijian; Hu Qingyuan; Si Fenni; Feng Jinghua; Zhang Faqiang; Chen Jinchuan; Li Linbo; Chen Dingyang [Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900 (China); Ding Ning [Institute of Applied Physics and Computational Mathematics, Beijing 100088 (China); Zhou Xiuwen [Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900 (China)

2013-03-15T23:59:59.000Z

215

Varadhan and Mueller / Ablation Volume Rendering 1. Introduction  

E-Print Network [OSTI]

energy the material requires to change its state as well as its ability to absorb the incoming energy not just one phase change, as had been predicted previously, but two [3]. The ways in which heat propagates tissue. In the process of ablation, as heat energy impinges onto the material, the material responds

Mueller, Klaus

216

Towards Optimization of Probe Placement for Radio-Frequency Ablation  

E-Print Network [OSTI]

's electric potential and of the steady state of the heat distribution during RF ablation. The optimization with mono- or bipolar systems: A probe, connected to an electric generator, is placed inside the malignant tissue, such that an electric current flows through the body and heats the tissue near the probe up

Preusser, Tobias

217

Ultrafast electron beam imaging of femtosecond laser-induced plasma  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Ultrafast electron beam imaging of femtosecond laser-induced plasma Ultrafast electron beam imaging of femtosecond laser-induced plasma dynamics Title Ultrafast electron beam imaging of femtosecond laser-induced plasma dynamics Publication Type Journal Article Year of Publication 2010 Authors Li, Junjie, Xuan Wang, Zhaoyang Chen, Richard Clinite, Samuel S. Mao, Pengfei Zhu, Zhengming Sheng, Jie Zhang, and Jianming Cao Journal Journal of Applied Physics Volume 107 Issue 8 Date Published 03/2010 Keywords copper, electron beam applications, high-speed optical techniques, laser ablation, plasma diagnostics, plasma production by laser Abstract Plasma dynamics in the early stage of laser ablation of a copper target are investigated in real time by making ultrafast electron shadow images and electron deflectometry measurements. These complementary techniques provide both a global view and a local perspective of the associated transient electric field and charge expansion dynamics. The results reveal that the charge cloud above the target surface is composed predominantly of thermally ejected electrons and that it is self-expanding, with a fast front-layer speed exceeding 107 m/s. The average electric field strength of the charge cloud induced by a pump fluence of 2.2 J/cm2 is estimated to be ∼ 2.4×105 V/m.

218

Time-resolved wavelength modulation spectroscopy measurements of HO2 kinetics  

E-Print Network [OSTI]

of the hydroperoxyl radical HO2 in a laser photolysis and long-path absorption pump-probe kinetics reactor with a near with a 1.5- m diode laser directly modulated at 5 MHz. The measured 2f WMS signal is calibrated by direct ab- sorbance of 1% or less , and the proportionality con- stant is established easily by comparison

219

Laser ignition  

DOE Patents [OSTI]

In the apparatus of the invention, a first excitation laser or other excitation light source is used in tandem with an ignitor laser to provide a compact, durable, engine deployable fuel ignition laser system. The beam from the excitation light source is split with a portion of it going to the ignitor laser and a second portion of it being recombined with the first portion after a delay before injection into the ignitor laser. Reliable fuel ignition is provided over a wide range of fuel conditions by using a single remote excitation light source for one or more small lasers located proximate to one or more fuel combustion zones.

Early, James W. (Los Alamos, NM); Lester, Charles S. (San Juan Pueblo, NM)

2002-01-01T23:59:59.000Z

220

Page 1Laser Safety Training Laser Institute of America Laser Safety Laser Institute of America  

E-Print Network [OSTI]

Page 1Laser Safety Training © Laser Institute of America 1 Laser Safety © Laser Institute of America Laser Safety: Hazards, Bioeffects, and Control Measures Laser Institute of America Gus Anibarro Education Manager 2Laser Safety © Laser Institute of America Laser Safety Overview Laser Safety Accidents

Farritor, Shane

Note: This page contains sample records for the topic "kinetics laser ablation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

Laser Telecommunication timeLaser beam  

E-Print Network [OSTI]

Laser Telecommunication Experiment Laser time Laser beam intensity timeLaser beam Laser battery Laser connected to a circuit without a modulator. Bottom graph illustrates what happen when a modulating signal is superimposed to the DC voltage driving the laser Laser beam intensity DC Input voltage DC

La Rosa, Andres H.

222

Plasmadynamics and ionization kinetics of thermionic energy conversion  

SciTech Connect (OSTI)

To reduce the plasma arc-drop, thermionic energy conversion is studied with both analytical and numerical tools. Simplifications are made in both the plasmadynamic and ionization-recombination theories. These are applied to a scheme proposed presently using laser irradiation to enhance the ionization kinetics of the thermionic plasma and thereby reduce the arc-drop. It is also predicted that it is possible to generate the required laser light from a thermionic-type Cesium plasma. The analysis takes advantage of theoretical simplifications derived for the ionization-recombination kinetics. It is shown that large laser ionization enhancements can occur and that collisional Cesium recombination lasing is expected. To complement the kinetic theory, a numerical method is developed to solve the thermionic plasma dynamics. The effects of the complete system of electron-atom inelastic collisions on the ionization-recombination problem are shown to reduce to a system nearly as simple as the well-known one-quantum approximation. To combine the above analysis of ionization-recombination kinetics with the plasma dynamics of thermionic conversion, a finite difference computer program is constructed. Using the above developments, a proposal to improve thermionic converter performance using laser radiation is considered. In this proposed scheme, laser radiation impinging on a thermionic plasma enhances the ionization process thereby raising the plasma density and reducing the plasma arc-drop. A source for such radiation may possibly be a Cesium recombination laser operating in a different thermionic converter. The possibility of this being an energy efficient process is discussed.

Lawless, J.L. Jr.

1981-01-01T23:59:59.000Z

223

Laser microphone  

DOE Patents [OSTI]

A microphone for detecting sound pressure waves includes a laser resonator having a laser gain material aligned coaxially between a pair of first and second mirrors for producing a laser beam. A reference cell is disposed between the laser material and one of the mirrors for transmitting a reference portion of the laser beam between the mirrors. A sensing cell is disposed between the laser material and one of the mirrors, and is laterally displaced from the reference cell for transmitting a signal portion of the laser beam, with the sensing cell being open for receiving the sound waves. A photodetector is disposed in optical communication with the first mirror for receiving the laser beam, and produces an acoustic signal therefrom for the sound waves.

Veligdan, James T. (Manorville, NY)

2000-11-14T23:59:59.000Z

224

DOE Center of Excellence in Medical Laser Applications. Final report  

SciTech Connect (OSTI)

An engineering network of collaborating medical laser laboratories are developing laser and optical technologies for medical diagnosis and therapy and are translating the engineering into medical centers in Portland, OR, Houston, TX, and Galveston, TX. The Center includes the University of Texas M.D. Anderson Cancer Center, the University of Texas-Austin, Texas A and M University, Rice University, the University Texas Medical Branch-Galveston, Oregon Medical Laser Center (Providence St. Vincent Medical Center, Oregon Health Sciences University, and Oregon Graduate Institute, Portland, OR), and the University of Oregon. Diagnostics include reflectance, fluorescence, Raman IR, laser photoacoustics, optical coherence tomography, and several new video techniques for spectroscopy and imaging. Therapies include photocoagulation therapy, laser welding, pulsed laser ablation, and light-activated chemotherapy of cancer (photodynamic therapy, or PDT). Medical applications reaching the clinic include optical monitoring of hyperbilirubinemia in newborns, fluorescence detection of cervical dysplasia, laser thrombolysis of blood clots in heart attack and brain stroke, photothermal coagulation of benign prostate hyperplasia, and PDT for both veterinary and human cancer. New technologies include laser optoacoustic imaging of breast tumors and hemorrhage in head trauma and brain stroke, quality control monitoring of dosimetry during PDT for esophageal and lung cancer, polarization video reflectometry of skin cancer, laser welding of artificial tissue replacements, and feedback control of laser welding.

Jacques, S.L. (Oregon Medical Laser Center, Portland, OR (United States))

1998-01-01T23:59:59.000Z

225

INFRARED ABSORPTION SPECTROSCOPY AND CHEMICAL KINETICS OF FREE RADICALS  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

mNAL PERFORMANCE REPORT mNAL PERFORMANCE REPORT for INFRARED ABSORPTION SPECTROSCOPY AND CHEMICAL KINETICS OF FREE RADICALS DE-FG05-85ER13439 1-AUG-1985 to 31-JUL-1994 Robert F. Curl and Graham P. Glass Principal Investigators Introduction This research was directed at the detection, monitoring, and study (by infrared absorption spectroscopy) of the chemical kinetic behavior of small free radical species thought to be important intermediates in combustion. The work typically progressed from the detection and analysis of the infrared spectrum of combustion radical to the utilization of the infrared spectrum thus obtained in the investigation of chemical kinetics of the radical species. The methodology employed was infrared kinetic spectroscopy. In this technique the radical is produced by UV flash photolysis using an excimer laser and then

226

Dynamics of femtosecond laser produced tungsten nanoparticle plumes  

SciTech Connect (OSTI)

We investigated the expansion features of femtosecond laser generated tungsten nanoparticle plumes in vacuum. Fast gated images showed distinct two components expansion features, viz., plasma and nanoparticle plumes, separated by time of appearance. The persistence of plasma and nanoparticle plumes are ?500 ns and ?100 ?s, respectively, and propagating with velocities differed by 25 times. The estimated temperature of the nanoparticles showed a decreasing trend with increasing time and space. Compared to low-Z materials (e.g., Si), ultrafast laser ablation of high-Z materials like W provides significantly higher nanoparticle yield. A comparison between the nanoparticle plumes generated by W and Si is also discussed along with other metals.

Harilal, S. S.; Hassanein, A. [Center for Materials Under Extreme Environment, School of Nuclear Engineering, Purdue University, West Lafayette, Indiana 47907 (United States)] [Center for Materials Under Extreme Environment, School of Nuclear Engineering, Purdue University, West Lafayette, Indiana 47907 (United States); Farid, N. [Center for Materials Under Extreme Environment, School of Nuclear Engineering, Purdue University, West Lafayette, Indiana 47907 (United States) [Center for Materials Under Extreme Environment, School of Nuclear Engineering, Purdue University, West Lafayette, Indiana 47907 (United States); School of Physics and Optical Engineering, Dalian University of Technology, Dalian 116024 (China); Kozhevin, V. M. [Ioffe Physics Technical Institute, Russian Academy of Sciences, St. Petersburg 194021 (Russian Federation)] [Ioffe Physics Technical Institute, Russian Academy of Sciences, St. Petersburg 194021 (Russian Federation)

2013-11-28T23:59:59.000Z

227

Commercialization plan laser-based decoating systems  

SciTech Connect (OSTI)

F2 Associates Inc. (F2) is a small, high-technology firm focused on developing and commercializing environmentally friendly laser ablation systems for industrial-rate removal of surface coatings from metals, concrete, and delicate substrates such as composites. F2 has a contract with the US Department of Energy Federal Energy Technology Center (FETC) to develop and test a laser-based technology for removing contaminated paint and other contaminants from concrete and metal surfaces. Task 4.1 in Phase 2 of the Statement of Work for this DOE contract requires that F2 ``document its plans for commercializing and marketing the stationary laser ablation system. This document shall include a discussion of prospects for commercial customers and partners and may require periodic update to reflect changing strategy. This document shall be submitted to the DOE for review.`` This report is being prepared and submitted in fulfillment of that requirement. This report describes the laser-based technology for cleaning and coatings removal, the types of laser-based systems that have been developed by F2 based on this technology, and the various markets that are emerging for this technology. F2`s commercialization and marketing plans are described, including how F2`s organization is structured to meet the needs of technology commercialization, F2`s strategy and marketing approach, and the necessary steps to receive certification for removing paint from aircraft and DOE certification for D and D applications. The future use of the equipment built for the DOE contract is also discussed.

Freiwald, J.; Freiwald, D.A.

1998-01-01T23:59:59.000Z

228

Laser ignition  

DOE Patents [OSTI]

In the apparatus of the invention, a first excitation laser or other excitation light source is used in tandem with an ignitor laser to provide a compact, durable, engine deployable fuel ignition laser system. Reliable fuel ignition is provided over a wide range of fuel conditions by using a single remote excitation light source for one or more small lasers located proximate to one or more fuel combustion zones. In a third embodiment, alternating short and long pulses of light from the excitation light source are directed into the ignitor laser. Each of the embodiments of the invention can be multiplexed so as to provide laser light energy sequentially to more than one ignitor laser.

Early, James W. (Los Alamos, NM); Lester, Charles S. (San Juan Pueblo, NM)

2003-01-01T23:59:59.000Z

229

Ablative thermal management structural material on the hypersonic vehicles  

SciTech Connect (OSTI)

A hypersonic vehicle is designed to fly at high Mach number in the earth`s atmosphere that will result in higher aerodynamic heating loads on specific areas of the vehicle. A thermal protection system is required for these areas that may exceed the operating temperature limit of structural materials. This paper delineates the application of ablative material as the passive type of thermal protection system for the nose or wing leading edges. A simplified quasi-steady-state one-dimensional computer model was developed to evaluate the performance and thermal design of a leading edge. The detailed description of the governing mathematical equations and results are presented. This model provides a quantitative information to support the design estimate, performance optimization, and assess preliminary feasibility of using ablation as a design approach.

Shortland, H.; Tsai, C. [Rockwell International Corporation, Seal Beach, CA (United States)

1995-09-01T23:59:59.000Z

230

Proof of damage-free selective removal of thin dielectric coatings on silicon wafers by irradiation with femtosecond laser pulses  

SciTech Connect (OSTI)

The microstructural impact of selective femtosecond laser ablation of thin dielectric layers from monocrystalline silicon wafers was investigated. Various spots opened by 280 fs laser pulses at {lambda} = 1.03 {mu}m wavelength and 50 fs pulses at 800 nm, respectively, were analyzed in detail using Raman and transmission electron microscopy. The results show clearly that the thin dielectric films can be removed without any detectable modification of the Si crystal structure in the opened area. In contrast, in adjacent regions corresponding to laser fluence slightly below the breaking threshold, a thin layer of amorphous silicon with a maximum thickness of about 50 nm is found at the Si/SiO{sub 2} interface after laser irradiation. More than one pulse on the same position, however, causes structural modification of the silicon after thin film ablation in any case.

Rublack, Tino; Muchow, Markus [Zentrum fuer Innovationskompetenz SiLi-nano, Martin-Luther-Universitaet Halle-Wittenberg, 06120 Halle (Germany); Schade, Martin; Leipner, Hartmut S. [Interdisziplinaeres Zentrum fuer Materialwissenschaften, Martin-Luther-Universitaet Halle-Wittenberg, 06099 Halle (Germany); Seifert, Gerhard [Zentrum fuer Innovationskompetenz SiLi-nano, Martin-Luther-Universitaet Halle-Wittenberg, 06120 Halle (Germany); Fraunhofer-Center for Silicon Photovoltaics CSP, 06120 Halle (Germany)

2012-07-15T23:59:59.000Z

231

Metal-like self-organization of periodic nanostructures on silicon and silicon carbide under femtosecond laser pulses  

SciTech Connect (OSTI)

Periodic structures were generated on Si and SiC surfaces by irradiation with femtosecond laser pulses. Self-organized structures with spatial periodicity of approximately 600?nm appear on silicon and silicon carbide in the laser fluence range just above the ablation threshold and upon irradiation with a large number of pulses. As in the case of metals, the dependence of the spatial periodicity on laser fluence can be explained by the parametric decay of laser light into surface plasma waves. The results show that the proposed model might be universally applicable to any solid state material.

Gemini, Laura [Advanced Research Center for beam Science, Institute for Chemical Research, Kyoto University, 611-0011 Kyoto (Japan); Department of Physics, Graduate School of Science, Kyoto University, 606-85802 Kyoto (Japan); FNSPE, Czech Technical University in Prague, 11519 Prague (Czech Republic); HiLASE Project, Institute of Physics, ASCR, 18221 Prague (Czech Republic); Hashida, Masaki; Shimizu, Masahiro; Miyasaka, Yasuhiro; Inoue, Shunsuke; Tokita, Shigeki; Sakabe, Shuji [Advanced Research Center for beam Science, Institute for Chemical Research, Kyoto University, 611-0011 Kyoto (Japan); Department of Physics, Graduate School of Science, Kyoto University, 606-85802 Kyoto (Japan); Limpouch, Jiri [FNSPE, Czech Technical University in Prague, 11519 Prague (Czech Republic); Mocek, Tomas [HiLASE Project, Institute of Physics, ASCR, 18221 Prague (Czech Republic)

2013-11-21T23:59:59.000Z

232

Spectroscopy and kinetics of combustion gases at high temperatures  

SciTech Connect (OSTI)

This program involves two complementary activities: (1) development and application of cw ring dye laser absorption methods for sensitive detection of radical species and measurement of fundamental spectroscopic parameters at high temperatures; and (2) shock tube studies of reaction kinetics relevant to combustion. Species currently under investigation in the spectroscopic portion of the research include NO and CH{sub 3}; this has necessitated the continued operated at wavelengths in the range 210-230 nm. Shock tube studies of reaction kinetics currently are focussed on reactions involving CH{sub 3} radicals.

Hanson, R.K.; Bowman, C.T. [Stanford Univ., CA (United States)

1993-12-01T23:59:59.000Z

233

Laser ignition  

DOE Patents [OSTI]

In the apparatus of the invention, a first excitation laser or other excitation light source is used in tandem with an ignitor laser to provide a compact, durable, engine deployable fuel ignition laser system. Reliable fuel ignition is provided over a wide range of fuel conditions by using a single remote excitation light source for one or more small lasers located proximate to one or more fuel combustion zones. In the embodiment of the invention claimed herein, the beam from the excitation light source is split with a portion of it going to the ignitor laser and a second portion of it being combined with either the first portion after a delay before injection into the ignitor laser.

Early, James W. (Los Alamos, NM); Lester, Charles S. (San Juan Pueblo, NM)

2002-01-01T23:59:59.000Z

234

Fully-automatic laser welding and micro-sculpting with universal in situ inline coherent imaging  

E-Print Network [OSTI]

Though new affordable high power laser technologies make possible many processing applications in science and industry, depth control remains a serious technical challenge. Here we show that inline coherent imaging, with line rates up to 312 kHz and microsecond-duration capture times, is capable of directly measuring laser penetration depth in a process as violent as kW-class keyhole welding. We exploit ICI's high speed, high dynamic range and robustness to interference from other optical sources to achieve fully automatic, adaptive control of laser welding as well as ablation, achieving micron-scale sculpting in vastly different heterogeneous biological materials.

Webster, Paul J L; Ji, Yang; Galbraith, Christopher M; Kinross, Alison W; Van Vlack, Cole; Fraser, James M

2014-01-01T23:59:59.000Z

235

Laser ignition  

DOE Patents [OSTI]

In the apparatus of the invention, a first excitation laser or other excitation light source capable of producing alternating beams of light having different wavelengths is used in tandem with one or more ignitor lasers to provide a compact, durable, engine deployable fuel ignition laser system. Reliable fuel ignition is provided over a wide range of fuel conditions by using the single remote excitation light source for pumping one or more small lasers located proximate to one or more fuel combustion zones with alternating wavelengths of light.

Early, James W. (Los Alamos, NM); Lester, Charles S. (San Juan Pueblo, NM)

2002-01-01T23:59:59.000Z

236

Gold Nanoparticle-Assisted Laser Surface Modification of Borosilicate Glass Substrates  

Science Journals Connector (OSTI)

The laser irradiation allowed the splitting and fusion of NPs on the substrate surface and, at the same time, the formation of craters of less than 10 nm diameter at various places following one laser shot with a relatively high intensity of 460 or 370 mJcm?2pulse?1 but well below the breakdown threshold of 25?40 Jcm?2pulse?1. ... Another example supporting this conclusion is a CW 10.6 ?m CO2 laser-treated silica glass that allowed a facile wet etching by HF.(45) We note here that the degree of modification by exposure to the nanosecond UV laser is less remarkable than that observed for quartz exposed to femotosecond NIR lasers, which bring about the intensification of the D2 band and thus lead to a higher fictive temperature of the irradiated area. ... One-step microfabrication of fused silica by laser ablation of an organic solution ...

Shuichi Hashimoto; Takayuki Uwada; Masahide Hagiri; Hiroaki Takai; Tomoyuki Ueki

2009-11-10T23:59:59.000Z

237

Laser-matter interaction at intensities of 10 sup 12 W/cm sup 2 and below  

SciTech Connect (OSTI)

For single pulsed laser-matter interactions at sufficiently high intensity, the electron density in the ablated vapor is large enough to absorb the laser radiation before it can reach the dense target material. The resulting interaction can be described in terms of energy flows: laser energy is absorbed in the plasma in front of the target and reappears as thermal electron energy and secondary radiation, part of which impinges upon and heats the dense target material at the dense material-vapor interface. This heating in turn drives ablation, thereby providing a self-consistent mass source for the laser absorption, energy conversion, and transmission. Under typical conditions of laser intensity, pulse width and spot size, the flow patterns can be strongly two-dimensional. We have modified the inertial confinement fusion code LASNEX to simulate gaseous and some dense material aspects for the relatively low intensity, long-pulse-length conditions to interest in many laser-related applications. The unique aspect to our treatment consists of an ablation model which defines a dense material vapor interface and then calculates the mass flow across this interface. The model, at present, treats the dense material as a rigid, two-dimensional simulational mass and heat reservoir, suppressing all hydrodynamical motion in the dense material. The modeling is being developed and refined through simulation of experiments, as well as through the investigation of internal inconsistencies, and some simulations of model problems. 5 refs., 14 figs., 1 tab.

Goldman, S.R.; Dingus, R.S.; Kirkpatrick, R.C.; Kopp, R.A.; Stover, E.K.; Watt, R.G.

1990-01-01T23:59:59.000Z

238

CLEERS Coordination & Joint Development of Benchmark Kinetics...  

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

Kinetic Data CLEERS Coordination & Joint Development of Benchmark Kinetics for LNT & SCR CLEERS Coordination & Development of Catalyst Process Kinetic Data - Pres. 1:...

239

Kinetics Of Carbon Gasification  

Science Journals Connector (OSTI)

Kinetics Of Carbon Gasification ... The steamcarbon reaction, which is the essential reaction of the gasification processes of carbon-based feed stocks (e.g., coal and biomass), produces synthesis gas (H2 + CO), a synthetically flexible, environmentally benign energy source. ... Coal Gasification in CO2 and Steam:? Development of a Steam Injection Facility for High-Pressure Wire-Mesh Reactors ...

C. W. Zielke; Everett. Gorin

1957-03-01T23:59:59.000Z

240

LLNL Chemical Kinetics Modeling Group  

SciTech Connect (OSTI)

The LLNL chemical kinetics modeling group has been responsible for much progress in the development of chemical kinetic models for practical fuels. The group began its work in the early 1970s, developing chemical kinetic models for methane, ethane, ethanol and halogenated inhibitors. Most recently, it has been developing chemical kinetic models for large n-alkanes, cycloalkanes, hexenes, and large methyl esters. These component models are needed to represent gasoline, diesel, jet, and oil-sand-derived fuels.

Pitz, W J; Westbrook, C K; Mehl, M; Herbinet, O; Curran, H J; Silke, E J

2008-09-24T23:59:59.000Z

Note: This page contains sample records for the topic "kinetics laser ablation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

Laser device  

DOE Patents [OSTI]

A laser device includes a virtual source configured to aim laser energy that originates from a true source. The virtual source has a vertical rotational axis during vertical motion of the virtual source and the vertical axis passes through an exit point from which the laser energy emanates independent of virtual source position. The emanating laser energy is collinear with an orientation line. The laser device includes a virtual source manipulation mechanism that positions the virtual source. The manipulation mechanism has a center of lateral pivot approximately coincident with a lateral index and a center of vertical pivot approximately coincident with a vertical index. The vertical index and lateral index intersect at an index origin. The virtual source and manipulation mechanism auto align the orientation line through the index origin during virtual source motion.

Scott, Jill R. (Idaho Falls, ID); Tremblay, Paul L. (Idaho Falls, ID)

2008-08-19T23:59:59.000Z

242

Kinetic equilibrium and relativistic thermodynamics  

E-Print Network [OSTI]

Relativistic thermodynamics is treated from the point of view of kinetic theory. It is shown that the generalized J\\"uttner distribution suggested in [1] is compatible with kinetic equilibrium. The requirement of compatibility of kinetic and thermodynamic equilibrium reveals several generalizations of the Gibbs relation where the velocity field is an independent thermodynamic variable.

P. Vn

2011-02-01T23:59:59.000Z

243

Catheter Ablation for Atrial Fibrillation in Congestive Heart Failure  

Science Journals Connector (OSTI)

...of antiarrhythmic drugs is challenging, owing to the limited efficacy and potentially deleterious effects of the drugs. This finding has led to renewed interest in rate control, stimulated by reports on several important studies, particularly the Atrial Fibrillation Follow-up Investigation of Rhythm... In patients with heart failure, atrial fibrillation may exacerbate ventricular dysfunction and symptoms. In this study, catheter ablation was performed to restore sinus rhythm in patients with heart failure and refractory atrial fibrillation. The results show improvement in the left ventricular ejection fraction, symptoms, exercise capacity, and quality of life.

Hsu L.-F.; Jas P.; Sanders P.

2004-12-02T23:59:59.000Z

244

High temperature ablation resistance of ZrNp reinforced W matrix composites  

E-Print Network [OSTI]

modulus of elasticity, good thermal shock resistance, stiffness and good high temperature strengthHigh temperature ablation resistance of ZrNp reinforced W matrix composites Malik Adeel Umer microscopy (SEM) For the purpose of improving the high temperature ablation resistance of tungsten

Hong, Soon Hyung

245

Snow ablation modelling in a mature aspen stand of the boreal forest  

E-Print Network [OSTI]

subarea occupies 1200 km2 , with 40% of the area covered by evergreen conifer forest and 8% by deciduousSnow ablation modelling in a mature aspen stand of the boreal forest J. P. Hardy,1* R. E. Davis,1 R of components of energy transfer at the forest �oor. Our previous work successfully predicted snow ablation

Ni-Meister, Wenge

246

Pulsed laser irradiation of metal multilayers.  

SciTech Connect (OSTI)

Vapor-deposited, exothermic metal-metal multilayer foils are an ideal class of materials for detailed investigations of pulsed laser-ignited chemical reactions. Created in a pristine vacuum environment by sputter deposition, these high purity materials have well-defined reactant layer thicknesses between 1 and 1000 nm, minimal void density and intimate contact between layers. Provided that layer thicknesses are made small, some reactive metal-metal multilayer foils can be ignited at a point by laser irradiation and exhibit subsequent high-temperature, self-propagating synthesis. With this presentation, we describe the pulsed laser-induced ignition characteristics of a single multilayer system (equiatomic Al/Pt) that exhibits self-propagating synthesis. We show that the thresholds for ignition are dependent on (i) multilayer design and (ii) laser pulse duration. With regard to multilayer design effects on ignition, there is a large range of multilayer periodicity over which ignition threshold decreases as layer thicknesses are made small. We attribute this trend of decreased ignition threshold to reduced mass transport diffusion lengths required for rapid exothermic mixing. With regard to pulse duration effects, we have determined how ignition threshold of a single Al/Pt multilayer varies with pulse duration from 10{sup -2} to {approx} 10{sup -13} sec (wavelength and spot size are held constant). A higher laser fluence is required for ignition when using a single laser pulse {approx} 100 fs or 1 ps compared with nanosecond or microsecond exposure, and we attribute this, in part, to the effects of reactive material being ablated when using the shorter pulse durations. To further understand these trends and other pulsed laser-based processes, our discussion concludes with an analysis of the heat-affected depths in multilayers as a function of pulse duration.

Adams, David Price; McDonald, Joel Patrick

2010-11-01T23:59:59.000Z

247

Improving alternative fuel utilization: detailed kinetic combustion...  

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

alternative fuel utilization: detailed kinetic combustion modeling & experimental testing Improving alternative fuel utilization: detailed kinetic combustion modeling &...

248

Femtosecond laser fabrication of micro and nano-disks in single layer graphene using vortex Bessel beams  

SciTech Connect (OSTI)

We report the fabrication of micro and nano-disks in single layer chemical vapor deposition graphene on glass substrate using femtosecond laser ablation with vortex Bessel beams. The fabricated graphene disks with diameters ranging from 650?nm to 4??m were characterized by spatially resolved micro-Raman spectroscopy. The variation of ablation threshold was investigated as a function of the number of pulses showing an incubation effect. A very high degree of size control of the fabricated graphene disks is enabled using a sequence of femtosecond pulses with different vortex orders.

Wetzel, Benjamin, E-mail: benjamin.wetzel@femto-st.fr; Xie, Chen; Lacourt, Pierre-Ambroise; Dudley, John M.; Courvoisier, Francois [Dpartement d'Optique P.M. Duffieux, Institut FEMTO-ST, UMR6174 CNRS, Universit de Franche-Comt, 25030 Besanon (France)] [Dpartement d'Optique P.M. Duffieux, Institut FEMTO-ST, UMR6174 CNRS, Universit de Franche-Comt, 25030 Besanon (France)

2013-12-09T23:59:59.000Z

249

Laser goniometer  

DOE Patents [OSTI]

The laser goniometer is an apparatus which permits an operator to sight along a geologic feature and orient a collimated lamer beam to match the attitude of the feature directly. The horizontal orientation (strike) and the angle from horizontal (dip), are detected by rotary incremental encoders attached to the laser goniometer which provide a digital readout of the azimuth and tilt of the collimated laser beam. A microprocessor then translates the square wave signal encoder outputs into an ASCII signal for use by data recording equipment.

Fairer, George M. (Boulder, CO); Boernge, James M. (Lakewood, CO); Harris, David W. (Lakewood, CO); Campbell, DeWayne A. (Littleton, CO); Tuttle, Gene E. (Littleton, CO); McKeown, Mark H. (Golden, CO); Beason, Steven C. (Lakewood, CO)

1993-01-01T23:59:59.000Z

250

Task 12: Laser cleaning of contaminated painted surfaces. Semi-annual report, April 1, 1996--September 30, 1996  

SciTech Connect (OSTI)

Paint contaminated with radionuclides and other hazardous materials is common in Department of Energy (DOE) facilities. Facility decommissioning and decontamination requires the removal of contaminated paint. Paint removal technologies include laser- and abrasive-based systems. F2 Associates are utilizing a pulsed-repetition CO{sub 2} laser that produces a 2.5-cm x 2.5-cm beam which can be scanned across a 30- x 100-cm raster and, when placed on a robot, can be designed to clean any surface that the robot can be programmed to follow. Causing little or no damage to the substrate (concrete, steel, etc.), the laser ablates the material to be removed from a given surface. Ablated material is then pulled into a filtration and collection (VAC-PAC) system to prevent the hazardous substances from entering into the atmosphere. The VAC-PAC system deposits the ablated material into waste drums which may be removed from the system without compromising the integrity of the seal, allowing a new drum to be set up for collection without leakage of the ablated material into the atmosphere.

Grisanti, A.A.; Hassett, D.J.

1997-05-01T23:59:59.000Z

251

Method for materials deposition by ablation transfer processing  

DOE Patents [OSTI]

A method in which a thin layer of semiconducting, insulating, or metallic material is transferred by ablation from a source substrate, coated uniformly with a thin layer of said material, to a target substrate, where said material is desired, with a pulsed, high intensity, patternable beam of energy. The use of a patternable beam allows area-selective ablation from the source substrate resulting in additive deposition of the material onto the target substrate which may require a very low percentage of the area to be covered. Since material is placed only where it is required, material waste can be minimized by reusing the source substrate for depositions on multiple target substrates. Due to the use of a pulsed, high intensity energy source the target substrate remains at low temperature during the process, and thus low-temperature, low cost transparent glass or plastic can be used as the target substrate. The method can be carried out atmospheric pressures and at room temperatures, thus eliminating vacuum systems normally required in materials deposition processes. This invention has particular application in the flat panel display industry, as well as minimizing materials waste and associated costs.

Weiner, Kurt H. (San Jose, CA)

1996-01-01T23:59:59.000Z

252

Interpretation of time-of-flight distributions for neutral particles under pulsed laser evaporation using direct Monte Carlo simulation  

SciTech Connect (OSTI)

A theoretical study of the time-of-flight (TOF) distributions under pulsed laser evaporation in vacuum has been performed. A database of TOF distributions has been calculated by the direct simulation Monte Carlo (DSMC) method. It is shown that describing experimental TOF signals through the use of the calculated TOF database combined with a simple analysis of evaporation allows determining the irradiated surface temperature and the rate of evaporation. Analysis of experimental TOF distributions under laser ablation of niobium, copper, and graphite has been performed, with the evaluated surface temperature being well agreed with results of the thermal model calculations. General empirical dependences are proposed, which allow indentifying the regime of the laser induced thermal ablation from the TOF distributions for neutral particles without invoking the DSMC-calculated database.

Morozov, Alexey A., E-mail: morozov@itp.nsc.ru [Institute of Thermophysics SB RAS, 1 Lavrentyev Ave., 630090 Novosibirsk (Russian Federation)

2013-12-21T23:59:59.000Z

253

High resolution pulsed infrared cavity ringdown spectroscopy: Application to laser ablated carbon clusters  

E-Print Network [OSTI]

pass fractional absorption is 1 ppm. We observe a frequency dependent ringdown cavity transmission of 5 in molecular beams. © 2002 American Institute of Physics. DOI: 10.1063/1.1461825 INTRODUCTION Cavity ringdown rate of light trapped in a high finesse optical cavity. Since the decay rate is directly proportional

Cohen, Ronald C.

254

Atomistic Modeling of Short Pulse Laser Ablation of Metals: Connections between Melting, Spallation, and Phase Explosion  

E-Print Network [OSTI]

, and Phase Explosion Leonid V. Zhigilei,* Zhibin Lin, and Dmitriy S. Ivanov§ Department of Materials Science spallation to phase explosion is signified by an abrupt change in the composition of the ejected plume (from of thermodynamic stability of the target material (90% of the critical temperature) into a two-phase mixture

Zhigilei, Leonid V.

255

A surface plasmon model for laser ablation of Ag+ Ions from a roughened Ag surface  

Science Journals Connector (OSTI)

Experimental work by Shea and Compton1 suggests that Ag+ ions emitted from a roughened Ag surface irradiated by a nanosecond or...+ ion which also undergoes a small-impact parameter collision with another ion or ...

R. H. Ritchie; J. R. Manson; P. M. Echenique

1991-01-01T23:59:59.000Z

256

Surface Chemistry of Gold Nanoparticles Produced by Laser Ablation in Aqueous Media  

Science Journals Connector (OSTI)

Jean-Philippe Sylvestre , Suzie Poulin , Andrei V. Kabashin , Edward Sacher ,* Michel Meunier , and John H. T. Luong * ...

Jean-Philippe Sylvestre; Suzie Poulin; Andrei V. Kabashin; Edward Sacher; Michel Meunier; John H. T. Luong

2004-10-06T23:59:59.000Z

257

Highly Efficient and Controllable PEGylation of Gold Nanoparticles Prepared by Femtosecond Laser Ablation in Water  

Science Journals Connector (OSTI)

The second sample (abbreviated as chemically generated gold nanoparticle) was purchased from Ted Pella (Redding, CA) and was prepared via the standard sodium citrate reduction of tetrachloroaurate (HAuCl4) methodology. ... Sylvestre, J. P.; Poulin, S.; Kabashin, A. V.; Sacher, E.; Meunier, M.; Luong, J. H. T. J. Phys. ...

Wei Qian; Makoto Murakami; Yuki Ichikawa; Yong Che

2011-10-19T23:59:59.000Z

258

Penetratin-Conjugated Gold Nanoparticles ? Design of Cell-Penetrating Nanomarkers by Femtosecond Laser Ablation  

Science Journals Connector (OSTI)

Ted Thurn, K.; Brown, E. M. B.; Wu, A.; Vogt, A.; Lai, B.; Maser, J.; Paunesku, T.; Woloschak, G. E. Nanoscale Res. ... Sylvestre, J. P.; Poulin, S.; Kabashin, A. V.; Sacher, E.; Meunier, M.; Luong, J. H. T. J. Phys. ...

S. Petersen; A. Barchanski; U. Taylor; S. Klein; D. Rath; S. Barcikowski

2010-12-21T23:59:59.000Z

259

Spatio-temporal mapping of ablated species in ultrafast laser-produced graphite plasmas  

E-Print Network [OSTI]

cannot leave their lattice positions before pulse termination. This very large deposited intensity can, diamond-like carbon, carbon nanotubes and nanowires) have become a focus for numerous studies because of these carbon species. In this context, it was reported that carbon dimers have an essential role

Harilal, S. S.

260

Summer 2010 Pulsed Laser Ablation of solid targets in a liquid  

E-Print Network [OSTI]

. The electronic properties alone has already lead to advances in electronics, such as the graphene-enhanced battery. #12; The tip is made with graphite powder and a carbon-based glue. Mix a suitable ratio

Baltisberger, Jay H.

Note: This page contains sample records for the topic "kinetics laser ablation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

Polymer Stable Magnesium Nanocomposites Prepared by Laser Ablation for Efficient Hydrogen Storage  

E-Print Network [OSTI]

Hydrogen is a promising alternative energy carrier that can potentially facilitate the transition from fossil fuels to sources of clean energy because of its prominent advantages such as high energy density (142 MJ per kg), great variety of potential sources (for example water, biomass, organic matter), and low environmental impact (water is the sole combustion product). However, due to its light weight, the efficient storage of hydrogen is still an issue investigated intensely. Various solid media have been considered in that respect among which magnesium hydride stands out as a candidate offering distinct advantages. Recent theoretical work indicates that MgH2 becomes less thermodynamically stable as particle diameter decreases below 2 nm. Our DFT (density functional theory) modeling studies have shown that the smallest enthalpy change, corresponding to 2 unit-cell thickness (1.6 {\\AA} Mg/3.0{\\AA} MgH2) of the film, is 57.7 kJ/molMg. This enthalpy change is over 10 kJ per molMg smaller than that of the bulk...

Makridis, S S; Panagakos, G; Kikkinides, E S; Stubos, A K; Wagener, P; Barcikowski, S

2013-01-01T23:59:59.000Z

262

PROOF COPY 019605JAP Effect of pulsing parameters on laser ablative cleaning of copper oxides  

E-Print Network [OSTI]

of copper oxides Jie Zhang,a Youneng Wang, Peng Cheng, and Y. Lawrence Yao Department of Mechanical; accepted 23 January 2006 The characteristics of copper oxide removal are comparably investigated under. Experiments are carried out on copper samples having different oxide layer thicknesses. The copper oxide layer

Yao, Y. Lawrence

263

Enhancement of muonium emission rate from silica aerogel with a laser-ablated surface  

Science Journals Connector (OSTI)

......Japan 4 High Energy Accelerator Research Organization...Research Center for Nuclear Physics (RCNP), Osaka...aerogel surface into vacuum was studied for the...especially in a high-vacuum accelerator environment. In addition......

G. A. Beer; Y. Fujiwara; S. Hirota; K. Ishida; M. Iwasaki; S. Kanda; H. Kawai; N. Kawamura; R. Kitamura; S. Lee; W. Lee; G. M. Marshall; T. Mibe; Y. Miyake; S. Okada; K. Olchanski; A. Olin; H. Ohnishi; Y. Oishi; M. Otani; N. Saito; K. Shimomura; P. Strasser; M. Tabata; D. Tomono; K. Ueno; E. Won; K. Yokoyama

2014-09-01T23:59:59.000Z

264

Laser Ablation Synthesis and Electron Transport Studies of Tin Oxide Nanowires**  

E-Print Network [OSTI]

and solar cells.[7±9] In addition, SnO2 thin films have been extensively studied and used as chemical demonstrated to work as sensitive UV and polarized UV detectors. A quartz tube furnace was used for our SnO2 of the furnace, and Si±SiO2 sub- strates covered with 20 nm gold catalytic clusters were placed in the middle

Zhou, Chongwu

265

Detailed study of nuclear fusion from femtosecond laser-driven explosions of deuterium clusters  

E-Print Network [OSTI]

Detailed study of nuclear fusion from femtosecond laser-driven explosions of deuterium clusters J that these clusters can explode with sufficient kinetic energy to drive nuclear fusion. Irradiating deuterium clusters

Ditmire, Todd

266

Pulsed Laser Deposition | EMSL  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Pulsed Laser Deposition Pulsed Laser Deposition EMSL's pulsed laser deposition (PLD) system is designed for epitaxial growth of oxide, ceramic, or synthetic mineral thin films and...

267

Laser barometer  

SciTech Connect (OSTI)

This paper describes an invention of a pressure measuring instrument which uses laser radiation to sense the pressure in an enclosed environment by means of measuring the change in refractive index of a gas - which is pressure dependent.

Abercrombie, K.R.; Shiels, D.; Rash, T.

1998-04-01T23:59:59.000Z

268

LASER ACCELERATORS  

E-Print Network [OSTI]

UNIVERSITY OF CALIFORNIA Accelerator & Fusion Researchat the 1983 Particle Accelerator Conference, Santa Fe, NM,March 21-23, 1983 LASER ACCELERATORS A.M. Sessler TWO-WEEK

Sessler, A.M.

2008-01-01T23:59:59.000Z

269

Laser ignition  

Science Journals Connector (OSTI)

Due to their thermodynamic benefits, second-generation spark-ignition engines with gasoline direct injection systems have ... combination of a spray-guided combustion process with laser-induced ignition allows th...

Bernhard Geringer; Dominikus Klawatsch; Josef Graf; Hans Peter Lenz

2004-03-01T23:59:59.000Z

270

Elemental and isotopic analysis of inorganic salts by laser desorption ionization mass spectrometry  

SciTech Connect (OSTI)

Laser desorption ionization mass spectrometry is applied for the analysis of elements as well as their isotopic composition in different inorganic salts. At very low laser energies the inorganic ions are desorbed and ionized from the thin layer of the sample surface. The naturally occurring isotopes of alkali and silver ions are resolved using time of flight mass spectrometer. Further increase in laser energy shows the appearance of Al, Cr, and Fe ions in the mass spectra. This indicates the penetration laser beam beyond the sample surface leading to the ablation of sample target at higher energies. The simultaneous appearance of atomic ions from the sample target at relatively higher laser energies hampers the unambiguous identification of amino acid residues from the biomolecular ions in MALDI-MS.

Jayasekharan, T.; Sahoo, N. K. [Applied Spectroscopy Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India)

2013-02-05T23:59:59.000Z

271

Laser EYE SURGERY LASIK and Excimer Lasers  

E-Print Network [OSTI]

Laser EYE SURGERY LASIK and Excimer Lasers Michael Hutchins #12;The PROBLEM opia - near sightedness - Laser Assisted in SItu Keratomileusis atomileusis is the procedure of opening the eye and ring the cornea. SIK uses an excimer laser to perform the alterations an er a knife or a femtosecond laser

Fygenson, Deborah Kuchnir

272

Long-term outcomes of adjunctive complex fractionated electrogram ablation to pulmonary vein isolation as treatment for non-paroxysmal atrial fibrillation  

Science Journals Connector (OSTI)

The adjunctive ablation of areas of complex fractionated electrogram (CFE) to pulmonary vein isolation (PVI) is...

Alessandro De Bortoli; Ole-Jrgen Ohm

2013-10-01T23:59:59.000Z

273

Influence of pulse width and target density on pulsed laser deposition of thin YBaCuO film.  

SciTech Connect (OSTI)

We have studied the effects of temporal pulse width and target density on the deposition of thin films of YBaCuO. A 248nm excimer laser and an 825nm Ti-sapphire laser were used to conduct the experiments with pulse widths of 27 ns, 16 ns, and 150 fs, and target densities of 80% and 90%. Scanning electron microscope photomicrographs and profilometer traces show a striking difference between nanosecond and femtosecond laser irradiation. Shortening the pulse width reduced particulate formation, provided stoichiometry, and improved the film properties. Decreasing the target density raised the ablation rate, produced thicker but nonuniform films, and reduced particulate formation.

Vikram, S.

1999-01-20T23:59:59.000Z

274

Chemical kinetics modeling  

SciTech Connect (OSTI)

This project emphasizes numerical modeling of chemical kinetics of combustion, including applications in both practical combustion systems and in controlled laboratory experiments. Elementary reaction rate parameters are combined into mechanisms which then describe the overall reaction of the fuels being studied. Detailed sensitivity analyses are used to identify those reaction rates and product species distributions to which the results are most sensitive and therefore warrant the greatest attention from other experimental and theoretical research programs. Experimental data from a variety of environments are combined together to validate the reaction mechanisms, including results from laminar flames, shock tubes, flow systems, detonations, and even internal combustion engines.

Westbrook, C.K.; Pitz, W.J. [Lawrence Livermore National Laboratory, CA (United States)

1993-12-01T23:59:59.000Z

275

Survival after Radiofrequency Ablation in 122 Patients with Inoperable Colorectal Lung Metastases  

SciTech Connect (OSTI)

Purpose. To analyze the factors associated with favorable survival in patients with inoperable colorectal lung metastases treated with percutaneous image-guided radiofrequency ablation. Methods. Between 2002 and 2011, a total of 398 metastases were ablated in 122 patients (87 male, median age 68 years, range 29-90 years) at 256 procedures. Percutaneous CT-guided cool-tip radiofrequency ablation was performed under sedation/general anesthesia. Maximum tumor size, number of tumors ablated, number of procedures, concurrent/prior liver ablation, previous liver or lung resection, systemic chemotherapy, disease-free interval from primary resection to lung metastasis, and survival from first ablation were recorded prospectively. Kaplan-Meier analysis was performed, and factors were compared by log rank test. Results. The initial number of metastases ablated was 2.3 (range 1-8); the total number was 3.3 (range 1-15). The maximum tumor diameter was 1.7 (range 0.5-4) cm, and the number of procedures was 2 (range 1-10). The major complication rate was 3.9 %. Overall median and 3-year survival rate were 41 months and 57 %. Survival was better in patients with smaller tumors-a median of 51 months, with 3-year survival of 64 % for tumors 2 cm or smaller versus 31 months and 44 % for tumors 2.1-4 cm (p = 0.08). The number of metastases ablated and whether the tumors were unilateral or bilateral did not affect survival. The presence of treated liver metastases, systemic chemotherapy, or prior lung resection did not affect survival. Conclusion. Three-year survival of 57 % in patients with inoperable colorectal lung metastases is better than would be expected with chemotherapy alone. Patients with inoperable but small-volume colorectal lung metastases should be referred for ablation.

Gillams, Alice, E-mail: alliesorting@gmail.com [The London Clinic, Radiology Department (United Kingdom); Khan, Zahid [Countess of Chester Hospital (United Kingdom); Osborn, Peter [Queen Alexandra Hospital (United Kingdom); Lees, William [University College London Medical School (United Kingdom)

2013-06-15T23:59:59.000Z

276

Laser Safety Introduction  

E-Print Network [OSTI]

Laser Safety #12;Introduction · A Laser is a device that controls the way energized atoms release photons. · LASER is an acronym for "Light Amplification by Stimulated Emission of Radiation" · The light emitted by a laser is non

McQuade, D. Tyler

277

Along the Laser Beampath  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

8 20 | Next | Last Back to Index NIF Laser Bay Each NIF laser bay is 122 meters (400 feet) long and contains 96 beamlines. This side view of Laser Bay 2 shows the four-high laser...

278

DOE Center of Excellence in Medical Laser Applications. Final report, December 1, 1994--November 30, 1997  

SciTech Connect (OSTI)

An engineering network of collaborating medical laser laboratories are developing laser and optical technologies for medical diagnosis and therapy and are translating the engineering into medical centers in Portland OR, Houston TX, and Galveston TX. The Center includes the University of Texas M.D. Anderson Cancer Center, the University of Texas-Austin, Texas A and M University, Rice University, the University Texas Medical Branch-Galveston, Oregon Medical Laser Center (Providence St. Vincent Medical Center, Oregon Health Sciences University, and Oregon Graduate Institute, Portland, OR), and the University of Oregon. Diagnostics include reflectance, fluorescence, Raman IR, laser photoacoustics, optical coherence tomography, and several new video techniques for spectroscopy and imaging. Therapies include photocoagulation therapy, laser welding, pulsed laser ablation, and light-activated chemotherapy of cancer (photodynamic therapy, or PDT). Medical applications reaching the clinic include optical monitoring of hyperbilirubinemia in newborns, fluorescence detection of cervical dysplasia, laser thrombolysis of blood clots in heart attack and brain stroke, photothermal coagulant of benign prostate hyperplasia, and PDT for both veterinary and human cancer. New technologies include laser optoacoustic imaging of breast tumors and hemorrhage in head trauma and brain stroke, quality control monitoring of dosimetry during PDT for esophageal and lung cancer, polarization video reflectometry of skin cancer, laser welding of artificial tissue replacements, and feedback control of laser welding.

Jacques, S.L.

1998-01-01T23:59:59.000Z

279

Physical characterization of ultrashort laser pulse drilling of biological tissue  

SciTech Connect (OSTI)

Ultrashort laser pulse ablation removes material with low energy fluence required and minimal collateral damage. The ultimate usefulness of this technology for biomedical applications depends, in part, on characterization of the physical conditions attained and determination of the zone of shockwave and heat affected material in particular tissues. Detailed numerical modeling of the relevant physics (deposition, plasma formation, shockwave generation and propagation, thermal conduction) are providing this information. A wide range of time scales is involved, ranging from picosecond for energy deposition and peak pressure and temperature, to nanosecond for development of shockwave, to microsecond for macroscopic thermophysical response.

Feit, M.D.; Rubenchik, A.M.; Kim, B.M.; Da Silva, L.D.; Stuart, B.C.; Perry, M.D.

1997-07-21T23:59:59.000Z

280

Laser Cosmology  

E-Print Network [OSTI]

Recent years have seen tremendous progress in our understanding of the cosmos, which in turn points to even deeper questions to be further addressed. Concurrently the laser technology has undergone dramatic revolutions, providing exciting opportunity for science applications. History has shown that the symbiosis between direct observations and laboratory investigation is instrumental in the progress of astrophysics. We believe that this remains true in cosmology. Current frontier phenomena related to particle astrophysics and cosmology typically involve one or more of the following conditions: (1) extremely high energy events; (2) very high density, high temperature processes; (3) super strong field environments. Laboratory experiments using high intensity lasers can calibrate astrophysical observations, investigate underlying dynamics of astrophysical phenomena, and probe fundamental physics in extreme limits. In this article we give an overview of the exciting prospect of laser cosmology. In particular, we showcase its unique capability of investigating frontier cosmology issues such as cosmic accelerator and quantum gravity.

Pisin Chen

2014-02-24T23:59:59.000Z

Note: This page contains sample records for the topic "kinetics laser ablation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

Kinetics of the inner ring in the exciton emission pattern in coupled GaAs quantum wells  

Science Journals Connector (OSTI)

We report on the kinetics of the inner ring in the exciton emission pattern. The formation time of the inner ring following the onset of the laser excitation is found to be about 30 ns. The inner ring is also found to disappear within 4 ns after the laser termination. The latter process is accompanied by a jump in the photoluminescence (PL) intensity. The spatial dependence of the PL jump indicates that the excitons outside of the region of laser excitation, including the inner ring region, are efficiently cooled to the lattice temperature even during the laser excitation. The ring formation and disappearance are explained in terms of exciton transport and cooling.

A. T. Hammack, L. V. Butov, J. Wilkes, L. Mouchliadis, E. A. Muljarov, A. L. Ivanov, and A. C. Gossard

2009-10-29T23:59:59.000Z

282

Systems and methods for laser assisted sample transfer to solution for chemical analysis  

SciTech Connect (OSTI)

Systems and methods are described for laser ablation of an analyte from a specimen and capturing of the analyte in a dispensed solvent to form a testing solution. A solvent dispensing and extraction system can form a liquid microjunction with the specimen. The solvent dispensing and extraction system can include a surface sampling probe. The laser beam can be directed through the surface sampling probe. The surface sampling probe can also serve as an atomic force microscopy probe. The surface sampling probe can form a seal with the specimen. The testing solution including the analyte can then be analyzed using an analytical instrument or undergo further processing.

Van Berkel, Gary J.; Kertesz, Vilmos; Ovchinnikova, Olga S.

2014-06-03T23:59:59.000Z

283

Systems and methods for laser assisted sample transfer to solution for chemical analysis  

DOE Patents [OSTI]

Systems and methods are described for laser ablation of an analyte from a specimen and capturing of the analyte in a dispensed solvent to form a testing solution. A solvent dispensing and extraction system can form a liquid microjunction with the specimen. The solvent dispensing and extraction system can include a surface sampling probe. The laser beam can be directed through the surface sampling probe. The surface sampling probe can also serve as an atomic force microscopy probe. The surface sampling probe can form a seal with the specimen. The testing solution including the analyte can then be analyzed using an analytical instrument or undergo further processing.

Van Berkel, Gary J; Kertesz, Vilmos; Ovchinnikova, Olga S

2013-08-27T23:59:59.000Z

284

Photoacoustic study of relaxation dynamics in multibubble systems in laser-superheated water  

Science Journals Connector (OSTI)

Microsecond relaxation dynamics in a cavitating surface layer of bulk water superheated by a TEA CO2 laser was studied using contact broadband photoacoustic spectroscopy. Damped nanosecond and microsecond oscillatory pressure-tension cycles recorded by an acoustic transducer are related to oscillations of steam bubbles of different sizes exhibiting strong dissipative losses and collective (coalescence and percolation) phenomena. These measurements also give important insight into basic parameters, characteristic spatial and temporal scales, and the mechanism of laser ablation of absorbing liquids in the thermal confinement regime.

Sergey I. Kudryashov; Kevin Lyon; Susan D. Allen

2006-05-04T23:59:59.000Z

285

Monitoring of Focus Position During Laser Processing based on Plasma Emission  

Science Journals Connector (OSTI)

Abstract The effects of lens-to-sample distance on plasma emission induced during laser processing were investigated. For tight focusing conditions, a local minimum value of emission intensity was observed for opaque materials. It was attributed to a reduction of ablation efficiency due to saturation. This effect can lead to identify the lens-to-sample distance that produces the highest fluence on the sample. A strategy to detect the working focus position based on monitoring the intensity of plasma emission was proposed. Variations of laser energy, pulse overlap and material type were also studied.

D. Diego-Vallejo; D. Ashkenasi; H.J. Eichler

2013-01-01T23:59:59.000Z

286

Ethanol ablation of benign thyroid cysts and predominantly cystic thyroid nodules: factors that predict outcome  

Science Journals Connector (OSTI)

No study has so far investigated the relationship between aspirate color or degree of aspiration on the success of ethanol ablation (EA) of cystic thyroid nodules. ... degree of aspiration, and volume of injected...

Hyun Sin In; Dong Wook Kim; Hye Jung Choo; Soo Jin Jung; Taewoo Kang

2014-05-01T23:59:59.000Z

287

Studies of the impurity pellet ablation in the high-temperature plasma of magnetic confinement devices  

Science Journals Connector (OSTI)

The ablation of impurity pellets in tokamak and stellarator plasmas is investigated. Different mechanisms for shielding the heat fluxes from the surrounding plasma to the pellet surface are discussed. A model ...

V. Yu. Sergeev; O. A. Bakhareva; B. V. Kuteev; M. Tendler

2006-05-01T23:59:59.000Z

288

Comparison of EUV spectral and ion emission features from laser-produced Sn and Li plasmas  

E-Print Network [OSTI]

Comparison of EUV spectral and ion emission features from laser- produced Sn and Li plasmas R. W. Coons, D. Campos, M. Crank, S. S. Harilal, and A. Hassanein School of Nuclear Engineering, and Center, and the kinetic energies and fluxes of ions at various laser intensities for both Sn and Li plasmas. The maximum

Harilal, S. S.

289

Beamed Energy Propulsion by Means of Target Ablation  

SciTech Connect (OSTI)

This paper describes hundreds of pendulum tests examining the beamed energy conversion efficiency of different metal targets coated with multiple liquid enhancers. Preliminary testing used a local laser with photographic paper targets, with no liquid, water, canola oil, or methanol additives. Laboratory experimentation was completed at Wright-Patterson AFB using a high-powered laser, and ballistic pendulums of aluminum, titanium, or copper. Dry targets, and those coated with water, methanol and oil were repeatedly tested in laboratory conditions. Results were recorded on several high-speed digital video cameras, and the conversion efficiency was calculated. Paper airplanes successfully launched using BEP were likewise recorded.

Rosenberg, Benjamin A. [Hilton Head High School, Hilton Head Island, SC 29926 (United States)

2004-03-30T23:59:59.000Z

290

CLEERS Coordination & Joint Development of Benchmark Kinetics...  

Broader source: Energy.gov (indexed) [DOE]

CLEERS Coordination & Joint Development of Benchmark Kinetics for LNT & SCR CLEERS Coordination & Joint Development of Benchmark Kinetics for LNT & SCR 2012 DOE Hydrogen and Fuel...

291

CLEERS Coordination & Joint Development of Benchmark Kinetics...  

Broader source: Energy.gov (indexed) [DOE]

Joint Development of Benchmark Kinetics for LNT & SCR CLEERS Coordination & Joint Development of Benchmark Kinetics for LNT & SCR 2011 DOE Hydrogen and Fuel Cells Program, and...

292

CLEERS Coordination & Development of Catalyst Process Kinetic...  

Broader source: Energy.gov (indexed) [DOE]

CLEERS Coordination & Development of Catalyst Process Kinetic Data CLEERS Coordination & Development of Catalyst Process Kinetic Data 2009 DOE Hydrogen Program and Vehicle...

293

Direct Observation of Aggregative Nanoparticle Growth: Kinetic...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Aggregative Nanoparticle Growth: Kinetic Modeling of the Size Distribution and Growth Rate. Direct Observation of Aggregative Nanoparticle Growth: Kinetic Modeling of the Size...

294

Multidimensional simulation and chemical kinetics development...  

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

Developing chemical kinetic mechanisms and applying them to simulating engine combustion processes. deer09aceves.pdf More Documents & Publications Chemical Kinetic Research on...

295

Effects of the pulse duration in laser modification of nano-sized WTi film on Si  

Science Journals Connector (OSTI)

A study of morphological and composition changes of the WTi/Si system induced by nanosecond and picosecond laser pulses is presented. A 190nm thick WTi film was deposited on a silicon substrate of n-type (100). The pulsed laser systems used were: nanosecond TEA CO2 laser (emission, 10.6m; pulse FWHM; pulse duration 120ns) and picosecond Nd:YAG laser (emission, 532nm; pulse FWHM; pulse duration 40ps). During experiments the used fluences (?) had similar values, ?1 = 20Jcm ? 2 in case of the TEA CO2 laser and ?2 = 16Jcm ? 2 for the Nd:YAG laser. The laser-induced morphological and composition modifications showed a dependence on pulse duration. Generally, the following morphological changes were observed: (i)ablation/exfoliation of the WTi thin film, (ii)appearance of hydrodynamic features such as resolidified material, and (iii)formation of nano-sized grains and globules. Overall morphological modifications were more pronounced after the picosecond laser action. The surface composition analysis showed a quite different distribution of sample components depending on the pulse duration. Formation of the silicon dioxide (SiO2) was recorded only in the case of irradiation of the WTi/Si system by picosecond laser pulses.

Suzana Petrovi?; D Peruko; D Milovanovi?; J Kova?; M ?ekada; P Panjan; B Gakovi?; M Trtica

2010-01-01T23:59:59.000Z

296

Surface modification of a \\{WTi\\} thin film on Si substrate by nanosecond laser pulses  

Science Journals Connector (OSTI)

Interaction of a nanosecond transversely excited atmospheric (TEA) CO2 laser, operating at 10.6?m, with tungstentitanium thin film (190nm) deposited on silicon of n-type (100) orientation, was studied. Multi-pulse irradiation was performed in air atmosphere with laser energy densities in the range 2449J/cm2. The energy absorbed from the laser beam was mainly converted to thermal energy, which generated a series of effects. The following morphological changes were observed: (i) partial ablation/exfoliation of the \\{WTi\\} thin film, (ii) partial modification of the silicon substrate with formation of polygonal grains, (iii) appearance of hydrodynamic features including nano-globules. Torch-like plumes started appearing in front of the target after several laser pulses.

S. Petrovi?; B. Gakovi?; D. Peruko; M. Trtica; B. Radak; P. Panjan; . Miljani?

2008-01-01T23:59:59.000Z

297

Driving high-gain shock-ignited inertial confinement fusion targets by green laser light  

SciTech Connect (OSTI)

Standard direct-drive inertial confinement fusion requires UV light irradiation in order to achieve ignition at total laser energy of the order of 1 MJ. The shock-ignition approach opens up the possibility of igniting fusion targets using green light by reducing the implosion velocity and laser-driven ablation pressure. An analytical model is derived, allowing to rescale UV-driven targets to green light. Gain in the range 100-200 is obtained for total laser energy in the range 1.5-3 MJ. With respect to the original UV design, the rescaled targets are less sensitive to irradiation asymmetries and hydrodynamic instabilities, while operating in the same laser-plasma interaction regime.

Atzeni, Stefano; Marocchino, Alberto; Schiavi, Angelo [Dipartimento SBAI, Universita di Roma 'La Sapienza' and CNISM, Via A. Scarpa 14-16, I-00161 Roma (Italy)

2012-09-15T23:59:59.000Z

298

Reciprocal Relations Between Kinetic Curves  

E-Print Network [OSTI]

We study coupled irreversible processes. For linear or linearized kinetics with microreversibility, $\\dot{x}=Kx$, the kinetic operator $K$ is symmetric in the entropic inner product. This form of Onsager's reciprocal relations implies that the shift in time, $\\exp (Kt)$, is also a symmetric operator. This generates reciprocity relations between kinetic curves. For example, for the Master equation, if we start the process from the $i$th pure state and measure the probability $p_j(t)$ of the $j$th state ($j\

Yablonsky, G S; Constales, D; Galvita, V; Marin, G B

2010-01-01T23:59:59.000Z

299

Kinetics and mechanisms of reactions involving small aromatic reactive intermediates  

SciTech Connect (OSTI)

Small aromatic radicals such as C{sub 6}H{sub 5}, C{sub 6}H{sub 5}O and C{sub 6}H{sub 4} are key prototype species of their homologs. C{sub 6}H{sub 5} and its oxidation product, C{sub 6}H{sub 5}O are believed to be important intermediates which play a pivotal role in hydrocarbon combustion, particularly with regard to soot formation. Despite their fundamental importance, experimental data on the reaction mechanisms and reactivities of these species are very limited. For C{sub 6}H{sub 5}, most kinetic data except its reactions with NO and NO{sub 2}, were obtained by relative rate measurements. For C{sub 6}H{sub 5}O, the authors have earlier measured its fragmentation reaction producing C{sub 5}H{sub 5} + CO in shock waves. For C{sub 6}H{sub 4}, the only rate constant measured in the gas phase is its recombination rate at room temperature. The authors have proposed to investigate systematically the kinetics and mechanisms of this important class of molecules using two parallel laser diagnostic techniques--laser resonance absorption (LRA) and resonance enhanced multiphoton ionization mass spectrometry (REMPI/MS). In the past two years, study has been focused on the development of a new multipass adsorption technique--the {open_quotes}cavity-ring-down{close_quotes} technique for kinetic applications. The preliminary results of this study appear to be quite good and the sensitivity of the technique is at least comparable to that of the laser-induced fluorescence method.

Lin, M.C. [Emory Univ., Atlanta, GA (United States)

1993-12-01T23:59:59.000Z

300

Chemical Looping Combustion Kinetics  

SciTech Connect (OSTI)

One of the most promising methods of capturing CO{sub 2} emitted by coal-fired power plants for subsequent sequestration is chemical looping combustion (CLC). A powdered metal oxide such as NiO transfers oxygen directly to a fuel in a fuel reactor at high temperatures with no air present. Heat, water, and CO{sub 2} are released, and after H{sub 2}O condensation the CO{sub 2} (undiluted by N{sub 2}) is ready for sequestration, whereas the nickel metal is ready for reoxidation in the air reactor. In principle, these processes can be repeated endlessly with the original nickel metal/nickel oxide participating in a loop that admits fuel and rejects ash, heat, and water. Our project accumulated kinetic rate data at high temperatures and elevated pressures for the metal oxide reduction step and for the metal reoxidation step. These data will be used in computational modeling of CLC on the laboratory scale and presumably later on the plant scale. The oxygen carrier on which the research at Utah is focused is CuO/Cu{sub 2}O rather than nickel oxide because the copper system lends itself to use with solid fuels in an alternative to CLC called 'chemical looping with oxygen uncoupling' (CLOU).

Edward Eyring; Gabor Konya

2009-03-31T23:59:59.000Z

Note: This page contains sample records for the topic "kinetics laser ablation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

Conservation laws and laser cooling of atoms  

E-Print Network [OSTI]

The straightforward application of energy and linear momentum conservation to the absorption/emission of photons by atoms--first outlined by Schr\\"odinger in 1922--allows to establish the essential features of laser cooling of two levels atoms at low laser intensities. The minimum attainable average kinetic energy of the atoms depends on the ratio $\\Gamma/E_R$ between the natural linewidth and the recoil energy and tends to $E_R$ as $\\Gamma/E_R$ tends to zero. This treatment is valid for any value of the ratio $\\Gamma/E_R$ and contains the semiclassical theory of laser cooling as the limiting case in which $E_R\\ll \\Gamma$.

Giuliani, Giuseppe

2015-01-01T23:59:59.000Z

302

Free electron laser amplifier driven by an induction linac  

SciTech Connect (OSTI)

This paper discusses the use of a free-electron laser amplifier as a means of converting the kinetic energy of an electron beam into coherent radiation. In particular, the use of an induction linear accelerator is discussed. The motion of the elections in the tapered and untapered wiggler magnets is discussed as well as the beam emittance, and the radiation fields involved. (LSP)

Neil, V.K.

1986-06-03T23:59:59.000Z

303

Ultrafast dynamic ellipsometry and spectroscopy of laser shocked materials  

SciTech Connect (OSTI)

Shock waves create extreme states of matter with very high pressures, temperatures, and volumetric compressions, at an exceedingly rapid rate of change. We review how to use a beamsplitter and a note card to turn a typical chirp pulse amplified femtosecond laser system into an ultrafast shock dynamics machine. Open scientific questions that can be addressed with such an apparatus are described. We report on the development of several single shot time resolved diagnostics needed to answer these questions. These single shot diagnostics are expected to be broadly applicable to other types of laser ablation experiments. Experimental results measured from shocked material dynamics of several systems are detailed. Finally, we report on progress towards using transient absorption as a measure of electronic excitation and coherent Raman as a picosecond probe of temperature in shock compressed condensed matter.

Mcgrane, Shawn David [Los Alamos National Laboratory; Bolme, Cindy B [Los Alamos National Laboratory; Whitley, Von H [Los Alamos National Laboratory; Moore, David S [Los Alamos National Laboratory

2010-01-01T23:59:59.000Z

304

Tunable, diode side-pumped Er:YAG laser  

DOE Patents [OSTI]

A discrete-element Er:YAG laser, side pumped by a 220 Watt peak-power InGaAs diode array, generates >500 mWatts at 2.94 {micro}m, and is tunable over a 6 nm range near about 2.936 {micro}m. The oscillator is a plano-concave resonator consisting of a concave high reflector, a flat output coupler, a Er:YAG crystal and a YAG intracavity etalon, which serves as the tuning element. The cavity length is variable from 3 cm to 4 cm. The oscillator uses total internal reflection in the Er:YAG crystal to allow efficient coupling of the diode emission into the resonating modes of the oscillator. With the tuning element removed, the oscillator produces up to 1.3 Watts of average power at 2.94 {micro}m. The duty factor of the laser is 6.5% and the repetition rate is variable up to 1 kHz. This laser is useful for tuning to an atmospheric transmission window at 2.935 {micro}m (air wavelength). The laser is also useful as a spectroscopic tool because it can access several infrared water vapor transitions, as well as transitions in organic compounds. Other uses include medical applications (e.g., for tissue ablation and uses with fiber optic laser scalpels) and as part of industrial effluent monitoring systems. 4 figs.

Hamilton, C.E.; Furu, L.H.

1997-04-22T23:59:59.000Z

305

Tunable, diode side-pumped Er: YAG laser  

DOE Patents [OSTI]

A discrete-element Er:YAG laser, side pumped by a 220 Watt peak-power InGaAs diode array, generates >500 mWatts at 2.94 .mu.m, and is tunable over a 6 nm range near about 2.936 .mu.m. The oscillator is a plano-concave resonator consisting of a concave high reflector, a flat output coupler, a Er:YAG crystal and a YAG intracavity etalon, which serves as the tuning element. The cavity length is variable from 3 cm to 4 cm. The oscillator uses total internal reflection in the Er:YAG crystal to allow efficient coupling of the diode emission into the resonating modes of the oscillator. With the tuning element removed, the oscillator produces up to 1.3 Watts of average power at 2.94 .mu.m. The duty factor of the laser is 6.5% and the repetition rate is variable up to 1 kHz. This laser is useful for tuning to an atmospheric transmission window at 2.935 .mu.m (air wavelength). The laser is also useful as a spectroscopic tool because it can access several infrared water vapor transitions, as well as transitions in organic compounds. Other uses include medical applications (e.g., for tissue ablation and uses with fiber optic laser scalpels) and as part of industrial effluent monitoring systems.

Hamilton, Charles E. (Bellevue, WA); Furu, Laurence H. (Modesto, CA)

1997-01-01T23:59:59.000Z

306

Theoretical Studies in Chemical Kinetics  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Theoretical Studies in Chemical Kinetics ^ ^ iCi| Theoretical Studies in Chemical Kinetics ^ ^ iCi| under AEC Contract A T (30-1)-3780 " ■ ' Annual Report (1970) Principal In-vestigator: Martin Karpins Institution: Harvard University The research performed under this contract can best be sunmarized under several headings. (a) Alkali-Halideg Alkali-Halide (MX^ M*X*) Exchange Reactions. This project is being continued. A careful study of certain

307

Jupiter Laser Facility  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Jupiter Laser Facility The commissioning of the Titan Petawatt-Class laser to LLNL's Jupiter Laser Facility (JLF) has provided a unique platform for the use of petawatt (PW)-class...

308

Hypersonic gasdynamic laser system  

SciTech Connect (OSTI)

This patent describes a visible, or near to mid infra-red, hypersonic gas dynamic laser system. It comprises: a hypersonic vehicle for carrying the hypersonic gas dynamic laser system, and also providing high energy ram air for thermodynamic excitation and supply of the laser gas; a laser cavity defined within the hypersonic vehicle and having a laser cavity inlet for the laser cavity formed by an opening in the hypersonic vehicle, such that ram air directed through the laser cavity opening supports gas dynamic lasing operations at wavelengths less than 10.6{mu} meters in the laser cavity; and an optical train for collecting the laser radiation from the laser cavity and directing it as a substantially collimated laser beam to an output aperture defined by an opening in the hypersonic vehicle to allow the laser beam to be directed against a target.

Foreman, K.M.; Maciulaitis, A.

1990-05-22T23:59:59.000Z

309

Terahertz quantum cascade lasers  

Science Journals Connector (OSTI)

...Michael Pepper Terahertz quantum cascade lasers Jerome Faist 1 Lassaad Ajili...developments in terahertz quantum cascade lasers are reviewed. Structures...magnetic confinement| Terahertz quantum cascade lasers. | Recent developments in...

2004-01-01T23:59:59.000Z

310

A Kinetic model of crack fusion  

Science Journals Connector (OSTI)

......Research Note A Kinetic model of crack fusion Zbigniew Czechowski Institute of Geophysics...presents a kinetic approach to the problem of fusion of cracks. A kinetic equation for the...repetitive episodes of seismicity. crack fusion|kinetic model|seismicity| References......

Zbigniew Czechowski

1991-02-01T23:59:59.000Z

311

Laser Desorption Analysis | EMSL  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Laser Desorption Analysis Laser Desorption Analysis EMSL offers a suite of instrumentation dedicated to understanding photoreactivity in the condensed phase, on surfaces, and at...

312

Laser Desorption Analysis | EMSL  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

neutral particle detection using a second multiphoton ionization or REMPI laser system; and UHV surface diagnostic equipment (AES, LEED, XPS). User Portal Name: Laser...

313

Laser Safety Management Policy Statement ............................................................................................................1  

E-Print Network [OSTI]

Laser Safety Management Policy Statement...........................................................2 Laser Users.............................................................................................................2 Unit Laser Safety Officer (ULSO

Davidson, Fordyce A.

314

Analysis of laser remote fusion cutting based on a mathematical model  

SciTech Connect (OSTI)

Laser remote fusion cutting is analyzed by the aid of a semi-analytical mathematical model of the processing front. By local calculation of the energy balance between the absorbed laser beam and the heat losses, the three-dimensional vaporization front can be calculated. Based on an empirical model for the melt flow field, from a mass balance, the melt film and the melting front can be derived, however only in a simplified manner and for quasi-steady state conditions. Front waviness and multiple reflections are not modelled. The model enables to compare the similarities, differences, and limits between laser remote fusion cutting, laser remote ablation cutting, and even laser keyhole welding. In contrast to the upper part of the vaporization front, the major part only slightly varies with respect to heat flux, laser power density, absorptivity, and angle of front inclination. Statistical analysis shows that for high cutting speed, the domains of high laser power density contribute much more to the formation of the front than for low speed. The semi-analytical modelling approach offers flexibility to simplify part of the process physics while, for example, sophisticated modelling of the complex focused fibre-guided laser beam is taken into account to enable deeper analysis of the beam interaction. Mechanisms like recast layer generation, absorptivity at a wavy processing front, and melt film formation are studied too.

Matti, R. S. [Department of Engineering Sciences and Mathematics, Lule University of Technology, S-971 87 Lule (Sweden); Department of Mechanical Engineering, College of Engineering, University of Mosul, Mosul (Iraq); Ilar, T.; Kaplan, A. F. H. [Department of Engineering Sciences and Mathematics, Lule University of Technology, S-971 87 Lule (Sweden)

2013-12-21T23:59:59.000Z

315

Laser Stabilization  

SciTech Connect (OSTI)

This book chapter covers the basics of the field of stabilizing lasers to optical frequency references such as optical cavities and molecular transitions via the application of servo control systems. These discussions are given with reference to the real-life frequency metrology experienced in Hall-Labs (now Ye-Labs), JILA, University of Colorado. The subjects covered include: the basics of control system stability, a discussion of both the theoretical and experimental limitations, an outline of optical cavity susceptibility to environmental noise, and a brief introduction to the use and limitations of molecular transitions as frequency references.

Hall, John L.; Taubman, Matthew S.; Ye, Jun

2010-01-01T23:59:59.000Z

316

Omega Laser Facility - Laboratory for Laser Energetics  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

- Laboratory for Laser Energetics Laboratory for Laser Energetics Logo Search Home Around the Lab Past Issues Past Quick Shots About Office of the Director Map to LLE LLE Tours LLE...

317

OMEGA Laser - Laboratory for Laser Energetics  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

- Laboratory for Laser Energetics Laboratory for Laser Energetics Logo Search Home Around the Lab Past Issues Past Quick Shots About Office of the Director Map to LLE LLE Tours LLE...

318

OMEGA Laser Drivers - Laboratory for Laser Energetics  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Drivers - Laboratory for Laser Energetics Laboratory for Laser Energetics Logo Search Home Around the Lab Past Issues Past Quick Shots About Office of the Director Map to LLE LLE...

319

The laser satellites communications and laser noises  

Science Journals Connector (OSTI)

The gain of advanced optical communication systems is reduced by the noise of optical source. Coherent optical communication systems are in particular very sensitive to the noise transmitter and local laser. Optical space communications is on the verge ... Keywords: laser, laser communication, noise limits, optical communication, range loss, satellite communications, satellite systems, signal transfer loss, space channel

Marketa Mazalkova

2008-08-01T23:59:59.000Z

320

Impulse coupling to targets in vacuum by KrF, HF, and CO/sub 2/ single-pulse lasers  

SciTech Connect (OSTI)

We present a laser-target scaling model which permits approximate prediction of the dependence of ablation pressure, mechanical coupling coefficient, and related parameters in vacuum upon single-pulse laser intensity (I), wavelength (lambda), and pulse width (tau) over extremely broad ranges. We show that existing data for vacuum mechanical coupling coefficient for metallic and endothermic nonmetallic, surface-absorbing planar targets follows this empirical trend to within a factor of 2 over 7 orders of magnitude in the product (Ilambda(tau)/sup 1/2/). The comparison we present is valid for intensity equal to or greater than the peak-coupling intensity I/sub max/, where dense

Phipps C.R. Jr.; Turner, T.P.; Harrison, R.F.; York, G.W.; Osborne, W.Z.; Anderson, G.K.; Corlis, X.F.; Haynes, L.C.; Steele, H.S.; Spicochi, K.C.; and others

1988-08-01T23:59:59.000Z

Note: This page contains sample records for the topic "kinetics laser ablation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

Method for continuous control of composition and doping of pulsed laser deposited films  

DOE Patents [OSTI]

A method for growing a deposit upon a substrate of semiconductor material involves the utilization of pulsed laser deposition techniques within a low-pressure gas environment. The substrate and a target of a first material are positioned within a deposition chamber and a low-pressure gas atmosphere is developed within the chamber. The substrate is then heated, and the target is irradiated, so that atoms of the target material are ablated from the remainder of the target, while atoms of the gas simultaneously are adsorbed on the substrate/film surface. The ablated atoms build up upon the substrate, together with the adsorbed gas atoms to form the thin-film deposit on the substrate. By controlling the pressure of the gas of the chamber atmosphere, the composition of the formed deposit can be controlled, and films of continuously variable composition or doping can be grown from a single target of fixed composition.

Lowndes, Douglas H. (Knoxville, TN); McCamy, James W. (Knoxville, TN)

1995-01-01T23:59:59.000Z

322

Method for continuous control of composition and doping of pulsed laser deposited films by pressure control  

DOE Patents [OSTI]

A method for growing a deposit upon a substrate of semiconductor material involves the utilization of pulsed laser deposition techniques within a low-pressure gas environment. The substrate and a target of a first material are positioned within a deposition chamber and a low-pressure gas atmosphere is developed within the chamber. The substrate is then heated, and the target is irradiated, so that atoms of the target material are ablated from the remainder of the target, while atoms of the gas simultaneously are adsorbed on the substrate/film surface. The ablated atoms build up upon the substrate, together with the adsorbed gas atoms to form the thin-film deposit on the substrate. By controlling the pressure of the gas of the chamber atmosphere, the composition of the formed deposit can be controlled, and films of continuously variable composition or doping can be grown from a single target of fixed composition.

Lowndes, Douglas H. (Knoxville, TN); McCamy, James W. (Knoxville, TN)

1996-01-01T23:59:59.000Z

323

Femtosecond kinetics of photoexcited carriers in germanium  

Science Journals Connector (OSTI)

Thermalization, intervalley scattering, and cooling of photoexcited carriers are observed in the indirect-band-gap semiconductor Ge through time-resolved direct-band-gap transmission and luminescence with 100-fs resolution. The transmission experiment, which uses ?=1.53 ?m, 120-fs pulses from a 76-MHz optical parametric oscillator takes advantage of the indirect-band-gap character of Ge to unambiguously determine the ??L intervalley scattering time at 295 K. The measured ??L transfer time for electrons at the ? valley edge is 23025 fs yielding 4.20.2108 eV/cm for the D?-L intervalley deformation potential. The luminescence experiments were performed at 10 K using a standard time and spectrally gated up-conversion technique employing an 82-MHz, 80-fs pulse width Ti:sapphire laser operating at ?=750 nm. From the luminescence experiments conducted with peak carrier densities of 10181019 cm-3, we observe that ??L,X scattering competes with carrier-carrier scattering so that nonthermalized carriers are observed for up to several hundred femtoseconds after an excitation pulse. Because the initial carrier kinetic energy is quite high we find that in addition to phonon-assisted L-L intervalley scattering, X-L and X-X processes must be included to account for a carrier-cooling time. A value of 5108 eV/cm is obtained for the DX-X deformation potential.

X. Q. Zhou; H. M. van Driel; G. Mak

1994-08-15T23:59:59.000Z

324

Hypersonic nonequilibrium Navier-Stokes solutions over an ablating graphite nosetip  

SciTech Connect (OSTI)

The general boundary conditions, including mass and energy balances, of chemically equilibrated or nonequilibrated gas adjacent to ablating surfaces have been derived. A computer procedure based on these conditions was developed and interfaced with the Navier-Stokes solver GASP (General Aerodynamics Simulation Program). A test case with a proposed hypersonic test-vehicle configuration and associated freestream conditions was developed. The solutions of the GASP code with various surface boundary conditions were obtained and compared with those of the ASCC (ABRES Shape Change) code, and the effect of nonequilibrium gas as well as surface chemistry on surface heating and ablation rate were examined. 22 refs.

Chen, Y.K.; Henline, W.D. [National Aeronautics and Space Administration, Ames Research Center, Moffett Field, CA (United States)

1994-09-01T23:59:59.000Z

325

Narrow gap laser welding  

DOE Patents [OSTI]

A laser welding process including: (a) using optical ray tracing to make a model of a laser beam and the geometry of a joint to be welded; (b) adjusting variables in the model to choose variables for use in making a laser weld; and (c) laser welding the joint to be welded using the chosen variables. 34 figs.

Milewski, J.O.; Sklar, E.

1998-06-02T23:59:59.000Z

326

Narrow gap laser welding  

DOE Patents [OSTI]

A laser welding process including: (a) using optical ray tracing to make a model of a laser beam and the geometry of a joint to be welded; (b) adjusting variables in the model to choose variables for use in making a laser weld; and (c) laser welding the joint to be welded using the chosen variables.

Milewski, John O. (Santa Fe, NM); Sklar, Edward (Santa Fe, NM)

1998-01-01T23:59:59.000Z

327

Short wavelength laser  

DOE Patents [OSTI]

A short wavelength laser is provided that is driven by conventional-laser pulses. A multiplicity of panels, mounted on substrates, are supported in two separated and alternately staggered facing and parallel arrays disposed along an approximately linear path. When the panels are illuminated by the conventional-laser pulses, single pass EUV or soft x-ray laser pulses are produced.

Hagelstein, P.L.

1984-06-25T23:59:59.000Z

328

Pulsed laser deposition to synthesize the bridge structure of artificial nacre: Comparison of nano- and femtosecond lasers  

SciTech Connect (OSTI)

Nature offers inspiration to new adaptive technologies that allow us to build amazing shapes and structures such as nacre using synthetic materials. Consequently, we have designed a pulsed laser ablation manufacturing process involving thin film deposition and micro-machining to create hard/soft layered 'brick-bridge-mortar' nacre of AlMgB{sub 14} (hard phase) with Ti (soft phase). In this paper, we report pulsed laser deposition (PLD) to mimic brick and bridge structures of natural nacre in AlMgB{sub 14}. Particulate formation inherent in PLD is exploited to develop the bridge structure. Mechanical behavior analysis of the AlMgB{sub 14}/Ti system revealed that the brick is to be 250 nm thick, 9 {mu}m lateral dimensions while the bridge (particle) is to have a diameter of 500 nm for a performance equivalent to natural nacre. Both nanosecond (ns) and femtosecond (fs) pulsed lasers were employed for PLD in an iterative approach that involves varying pulse energy, pulse repetition rate, and target-to-substrate distance to achieve the desired brick and bridge characteristics. Scanning electron microscopy, x-ray photoelectron spectroscopy, and optical profilometer were used to evaluate the film thickness, particle size and density, stoichiometry, and surface roughness of thin films. Results indicated that both ns-pulsed and fs-pulsed lasers produce the desired nacre features. However, each laser may be chosen for different reasons: fs-pulsed laser is preferred for much shorter deposition time, better stoichiometry, uniform-sized particles, and uniform film thickness, while ns-pulsed laser is favored for industrial acceptance, reliability, ease of handling, and low cost.

Melaibari, Ammar A. [Laboratory for Lasers, MEMS and Nanotechnology, Department of Mechanical Engineering, Iowa State University, Ames, Iowa 50011 (United States); Department of Mechanical Engineering, King AbdulAziz University, Jeddah 21589 (Saudi Arabia); Molian, Pal [Laboratory for Lasers, MEMS and Nanotechnology, Department of Mechanical Engineering, Iowa State University, Ames, Iowa 50011 (United States)

2012-11-15T23:59:59.000Z

329

Chemical kinetics and combustion modeling  

SciTech Connect (OSTI)

The goal of this program is to gain qualitative insight into how pollutants are formed in combustion systems and to develop quantitative mathematical models to predict their formation rates. The approach is an integrated one, combining low-pressure flame experiments, chemical kinetics modeling, theory, and kinetics experiments to gain as clear a picture as possible of the process in question. These efforts are focused on problems involved with the nitrogen chemistry of combustion systems and on the formation of soot and PAH in flames.

Miller, J.A. [Sandia National Laboratories, Livermore, CA (United States)

1993-12-01T23:59:59.000Z

330

Laser Glazing of Railroad Rails [Laser Applications Laboratory] - Nuclear  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Laser Glazing of Railroad Laser Glazing of Railroad Rails Capabilities Engineering Experimentation Reactor Safety Experimentation Aerosol Experiments System Components Laser Applications Overview Laser Oil & Gas Well Drilling Laser Heat Treatment Laser Welding of Metals On-line Monitoring Laser Beam Delivery Laser Glazing of Railroad Rails High Power Laser Beam Delivery Decontamination and Decommissioning Refractory Alloy Welding Robots Applications Other Facilities Other Capabilities Work with Argonne Contact us For Employees Site Map Help Join us on Facebook Follow us on Twitter NE on Flickr Laser Applications Laboratory Laser Glazing of Railroad Rails Project description: Laser glazing of rails. Category: Project with industrial partner (American Association of Railroads) Bookmark and Share

331

Laser Welding of Metals [Laser Applications Laboratory] - Nuclear  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Laser Welding of Metals Laser Welding of Metals Capabilities Engineering Experimentation Reactor Safety Experimentation Aerosol Experiments System Components Laser Applications Overview Laser Oil & Gas Well Drilling Laser Heat Treatment Laser Welding of Metals On-line Monitoring Laser Beam Delivery Laser Glazing of Railroad Rails High Power Laser Beam Delivery Decontamination and Decommissioning Refractory Alloy Welding Robots Applications Other Facilities Other Capabilities Work with Argonne Contact us For Employees Site Map Help Join us on Facebook Follow us on Twitter NE on Flickr Laser Applications Laboratory Laser Welding of Metals Project description: High-speed laser welding of metals. Category: Project with industrial partner (Delphi Energy and Engine Management Systems) Bookmark and Share

332

Laser-assisted nanomaterial deposition, nanomanufacturing, in situ monitoring and associated apparatus  

DOE Patents [OSTI]

Laser-assisted apparatus and methods for performing nanoscale material processing, including nanodeposition of materials, can be controlled very precisely to yield both simple and complex structures with sizes less than 100 nm. Optical or thermal energy in the near field of a photon (laser) pulse is used to fabricate submicron and nanometer structures on a substrate. A wide variety of laser material processing techniques can be adapted for use including, subtractive (e.g., ablation, machining or chemical etching), additive (e.g., chemical vapor deposition, selective self-assembly), and modification (e.g., phase transformation, doping) processes. Additionally, the apparatus can be integrated into imaging instruments, such as SEM and TEM, to allow for real-time imaging of the material processing.

Mao, Samuel S; Grigoropoulos, Costas P; Hwang, David J; Minor, Andrew M

2013-11-12T23:59:59.000Z

333

Preliminary Design of Laser - induced Breakd own Spectroscopy for Proto - MPEX  

SciTech Connect (OSTI)

Laser-induced breakdown spectroscopy (LIBS) is a technique for measuring surface matter composition. LIBS is performed by focusing laser radiation onto a target surface, ablating the surface, forming a plasma, and analyzing the light produced. LIBS surface analysis is a possible diagnostic for characterizing plasma-facing materials in ITER. Oak Ridge National Laboratory (ORNL) has enabled the initial installation of a laser-induced breakdown spectroscopy diagnostic on the prototype Material-Plasma Exposure eXperiment (Proto-MPEX), which strives to mimic the conditions found at the surface of the ITER divertor. This paper will discuss the LIBS implementation on Proto-MPEX, preliminary design of the fiber optic LIBS collection probe, and the expected results.

Shaw, Guinevere C [ORNL] [ORNL; Biewer, T.M. [Oak Ridge National Laboratory (ORNL)] [Oak Ridge National Laboratory (ORNL); Martin, Madhavi Z [ORNL] [ORNL; Martin, Rodger Carl [ORNL] [ORNL

2014-01-01T23:59:59.000Z

334

Heating Mechanisms in Short-Pulse Laser-Driven Cone Targets  

Science Journals Connector (OSTI)

The fast ignitor is a modern approach to laser fusion that uses a short-pulse laser to initiate thermonuclear burn. In its simplest form the laser launches relativistic electrons that carry its energy to a precompressed fusion target. Cones have been used to give the light access to the dense target core through the low-density ablative cloud surrounding it. Here the ANTHEM implicit hybrid simulation model shows that the peak ion temperatures measured in recent cone target experiments arose chiefly from return current joule heating, mildly supplemented by relativistic electron drag. Magnetic fields augment this heating only slightly, but capture hot electrons near the cone surface and force the hot electron stream into filaments.

R. J. Mason

2006-01-23T23:59:59.000Z

335

Desorption Kinetics of Methanol, Ethanol, and Water from Graphene...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Desorption Kinetics of Methanol, Ethanol, and Water from Graphene. Desorption Kinetics of Methanol, Ethanol, and Water from Graphene. Abstract: The desorption kinetics of methanol,...

336

PALM - Laser Capture Microdissection | EMSL  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

PALM - Laser Capture Microdissection PALM - Laser Capture Microdissection This Laser Capture Microdissection system is equipped with 100 x objective lens for enriching distinct...

337

Learn More about Fusion & Lasers  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

& Lasers How Lasers Work Learn how lasers were developed and how they work. Outreach NIF & Photon Science researchers take learning opportunities on the road. Glossary Don't...

338

Interest of Electrostimulation of Peripheral Motor Nerves during Percutaneous Thermal Ablation  

SciTech Connect (OSTI)

Purpose: We present our experience of utilizing peripheral nerve electrostimulation as a complementary monitoring technique during percutaneous thermal ablation procedures; and we highlight its utility and feasibility in the prevention of iatrogenic neurologic thermal injury. Methods: Peripheral motor nerve electrostimulation was performed in 12 patients undergoing percutaneous image-guided thermal ablations of spinal/pelvic lesions in close proximity to the spinal cord and nerve roots. Electrostimulation was used in addition to existing insulation (active warming/cooling with hydrodissection, passive insulation with CO{sub 2} insufflation) and temperature monitoring (thermocouples) techniques. Impending neurologic deficit was defined as a visual reduction of muscle response or need for a stronger electric current to evoke muscle contraction, compared with baseline. Results: Significant reduction of the muscle response to electrostimulation was observed in three patients during the ablation, necessitating temporary interruption, followed by injection of warm/cool saline. This resulted in complete recovery of the muscle response in two cases, while for the third patient the response did not improve and the procedure was terminated. No patient experienced postoperative motor deficit. Conclusion: Peripheral motor nerve electrostimulation is a simple, easily accessible technique allowing early detection of impending neurologic injury during percutaneous image-guided thermal ablation. It complements existing monitoring techniques and provides a functional assessment along the whole length of the nerve.

Tsoumakidou, Georgia, E-mail: gtsoumakidou@yahoo.com; Garnon, Julien, E-mail: juliengarnon@gmail.com; Ramamurthy, Nitin, E-mail: nitin_ramamurthy@hotmail.com; Buy, Xavier, E-mail: xbuy@ymail.com; Gangi, Afshin, E-mail: gangi@unistra.fr [University Hospital of Strasbourg (France)] [University Hospital of Strasbourg (France)

2013-12-15T23:59:59.000Z

339

Flyer Acceleration by Pulsed Ion Beam Ablation and Application for Space Propulsion  

SciTech Connect (OSTI)

Flyer acceleration by ablation plasma pressure produced by irradiation of intense pulsed ion beam has been studied. Acceleration process including expansion of ablation plasma was simulated based on fluid model. And interaction between incident pulsed ion beam and a flyer target was considered as accounting stopping power of it. In experiments, we used ETIGO-II intense pulsed ion beam generator with two kinds of diodes; 1) Magnetically Insulated Diode (MID, power densities of <100 J/cm2) and 2) Spherical-focused Plasma Focus Diode (SPFD, power densities of up to 4.3 kJ/cm2). Numerical results of accelerated flyer velocity agreed well with measured one over wide range of incident ion beam energy density. Flyer velocity of 5.6 km/s and ablation plasma pressure of 15 GPa was demonstrated by the present experiments. Acceleration of double-layer target consists of gold/aluminum was studied. For adequate layer thickness, such a flyer target could be much more accelerated than a single layer. Effect of waveform of ion beam was also examined. Parabolic waveform could accelerate more efficiently than rectangular waveform. Applicability of ablation propulsion was discussed. Specific impulse of 7000{approx}8000 seconds and time averaged thrust of up to 5000{approx}6000N can be expected. Their values can be controllable by changing power density of incident ion beam and pulse duration.

Harada, Nobuhiro; Buttapeng, Chainarong; Yazawa, Masaru [Department of Electrical Engineering, Nagaoka University of Technology, 1603 Kamitomioka, Nagaoka 940-2188 (Japan); Kashine, Kenji [Department of Electrical and Electronic Engineering, Kagoshima National College of Technology, 1460-1 Shinko, Hayato-cho, Aira-gun, Kagoshima 899-5193 (Japan); Jiang Weihua; Yatsui, Kiyoshi [Extreme Energy Density Research Institute, Nagaoka University of Technology, 1603 Kamitomioka, Nagaoka 940-2188 (Japan)

2004-02-04T23:59:59.000Z

340

A Dual-Armed Robotic System for Intraoperative Ultrasound Guided Hepatic Ablative Therapy:A  

E-Print Network [OSTI]

A Dual-Armed Robotic System for Intraoperative Ultrasound Guided Hepatic Ablative Therapy, we propose the use of a dual robotic arm system that manages both ultrasound manipulation and needle guidance. We report a prototype of the dual arm system and a comparative performance analysis between

Camesano, Terri

Note: This page contains sample records for the topic "kinetics laser ablation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

Ablation of carbon-based materials : investigation of roughness set-up from  

E-Print Network [OSTI]

Ablation of carbon-based materials : investigation of roughness set-up from heterogeneous reactions for roughness set-up is investigated, based on the coupling between diffusive transfer in the sur- rounding and heat transfers, the importance of which relies on the surface roughness. A new possible physical cause

Paris-Sud XI, Université de

342

Operational Analysis of Multiregional Nuclear Reactor Kinetics  

Science Journals Connector (OSTI)

......Operational Analysis of Multiregional Nuclear Reactor Kinetics NASSAR H. S. HAIDAR...analytically for a multiregional nuclear reactor whose subregions are of arbitrary...Operational Analysis of Multiregional Nuclear Reactor Kinetics NASSAU H. S. HAIDAR......

NASSAR H. S. HAIDAR

1983-05-01T23:59:59.000Z

343

Source flow chemical laser cavity performance  

SciTech Connect (OSTI)

The flow field in chemical optical cavities with source flow injectors is investigated. The 2-D coupled gasdynamics, chemical-vibrational-rotational kinetics, and multiline laser radiation equations are solved by using a stable implicit numerical method. The flow field-resonator interaction through the gain-intensity relations is calculated by linearization of the kinetics equations and application of an interative procedure. Calculated small signal gain distributions, closed cavity power variation with mode width, and intracavity spectral content are shown to be in close agreement with experimental measurements. A parametric study has also been conducted, and the potential improvements in performance are illustrated. The results indicate a strong dependency of optical power potential on fluid mechanical interactions with the injector cavity hardware.

Quan, V.; Vieceli, J.J.; Yang, T.T.

1984-05-01T23:59:59.000Z

344

BNL | CO2 Laser  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

CO2 Laser CO2 Laser The ATF is one of the only two facilities worldwide operating picosecond, terawatt-class CO2 lasers. Our laser system consists of a picoseconds pulse-injector based on fast optical switching from the output of a conventional CO2 laser oscillator, and a chain of high-pressure laser amplifiers. It starts with a wavelength converter wherein a near-IR picosecond solid-state laser with l»1 μm produces a mid-IR 10-μm pulse. This process employs two methods; semiconductor optical switching, and the Kerr effect. First, we combine the outputs from a multi-nanosecond CO2 laser oscillator with a picosecond Nd:YAG laser on a germanium Brewster-plate to produce an ~200 ps, 10μm pulse by semiconductor optical switching. Co-propagating this pulse with a Nd:YAG's 2nd harmonic in a

345

KINETIC ROUGHENING PHENOMENA, STOCHASTIC GROWTH, DIRECTED  

E-Print Network [OSTI]

KINETIC ROUGHENING PHENOMENA, STOCHASTIC GROWTH, DIRECTED POLYMERS AND ALL THAT Aspects 254 (1995) 215-414 Kinetic roughening phenomena, stochastic growth, directed polymers and all that for the nonlinear term 3.2. Dynamic RG analysis 3.3. A worthy detour: kinetic roughening with conservation law 3

Halpin-Healy, Tim

346

Slow Sorption Kinetics of Pentachlorophenol on Soil  

E-Print Network [OSTI]

Slow Sorption Kinetics of Pentachlorophenol on Soil: Concentration Effects J O H N P . D I V I N C of Delaware, Newark, Delaware 19717-1303 We investigated the sorption kinetics of pentachlorophenol (PCP in sorption. The onset of the slow sorption kinetics was also concentration dependent. At higher PCP

Sparks, Donald L.

347

14CME Kinetic Energy and Mass Kinetic energy is the energy that a  

E-Print Network [OSTI]

14CME Kinetic Energy and Mass Kinetic energy is the energy that a body has by virtue of its mass the table by determining the value of the missing entries using the formula for Kinetic Energy. Problem 2: What is the minimum and maximum range for the observed kinetic energies for the 10 CMEs? The largest

348

BNL | CFN Laser System Qualifications  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Laser System Qualification There are multiple laser systems at the CFN. Users who will be working with the following class 3B or 4 laser systems are required to complete the Laser...

349

In-situ plume diagnosis during pulsed laser deposition of epitaxial-oxide thin films  

SciTech Connect (OSTI)

The visible plume, induced during pulsed-laser deposition (PLD) of epitaxial La{sub 0.5}Sr{sub 0.5}CoO{sub 3}/Ba{sub 0.4}Sr{sub 0.6}TiO{sub 3}/La{sub 0.5}Sr{sub 0.5}CoO{sub 3}/YBa{sub 2}Cu{sub 3}O{sub 7}/YSZ heterostructures on silicon (100) wafers, was studied by optical-emission spectroscopy (OES). These films are suitable for the fabrication of ferroelectric capacitors and pyroelectric-sensor devices. A YAG laser, at 266 nm, is used for ablation. A collection lens transfers the PLD-plume emission into an optical fiber and onto a diffraction grating and a CCD array, for time-averaged spectroscopy from 410 to 640 nm. Plume emissions from ablated targets in the presence of an oxygen ambient, due to various atomic (Ba, Co, Cu, Sr, Ti, Y, Zr), ionic (Ba{sup +}, La{sup +}, Sr{sup +}, Y{sup +}), and a diatomic oxide (YO) species were identified. Emission intensity and evolution of ablated species are reported for distance away from the target surface, oxygen pressures, and laser fluences (1 to 4 J/cm{sup 2}). The behavior of reactive-product species, especially YO for plumes from yttria-stabilized zirconia (YSZ) and YBCO targets, is discussed. This simple and inexpensive OES system is suitable for use as a plume-quality monitor on routine PLD film synthesis.

Fenner, D.B.; Kung, P.J.; Goeres, J.; Li, Q. [AFR Inc., East Hartford, CT (United States)

1996-12-31T23:59:59.000Z

350

BUILDING A CHEMICAL LASER WEAPON  

Science Journals Connector (OSTI)

BUILDING A CHEMICAL LASER WEAPON ... Under fire, Airborne Laser program director confronts challenges of revolutionary weapons system ...

WILLIAM G. SCHULZ

2004-12-20T23:59:59.000Z

351

Estimating The Thermodynamics And Kinetics Of Chlorinated Hydrocarbon...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Estimating The Thermodynamics And Kinetics Of Chlorinated Hydrocarbon Degradation. Estimating The Thermodynamics And Kinetics Of Chlorinated Hydrocarbon Degradation. Abstract: Many...

352

Coulomb driven energy boost of heavy ions for laser plasma acceleration  

E-Print Network [OSTI]

An unprecedented increase of kinetic energy of laser accelerated heavy ions is demonstrated. Ultra thin gold foils have been irradiated by an ultra short laser pulse at an intensity of $6\\times 10^{19}$ W/cm$^{2}$. Highly charged gold ions with kinetic energies up to $> 200$ MeV and a bandwidth limited energy distribution have been reached by using $1.3$ Joule laser energy on target. $1$D and $2$D Particle in Cell simulations show how a spatial dependence on the ions ionization leads to an enhancement of the accelerating electrical field. Our theoretical model considers a varying charge density along the target normal and is capable of explaining the energy boost of highly charged ions, leading to a higher efficiency in laser acceleration of heavy ions.

Braenzel, J; Platonov, K; Klingsporn, M; Ehrentraut, L; Sandner, W; Schnrer, M

2014-01-01T23:59:59.000Z

353

Possibility of nuclear pumped laser experiment using low enriched uranium  

SciTech Connect (OSTI)

Possibility to perform experiments for nuclear pumped laser oscillation by using low enriched uranium is investigated. Kinetic analyses are performed for two types of reactor design, one is using highly enriched uranium and the other is using low enriched uranium. The reactor design is based on the experiment reactor in IPPE. The results show the oscillation of nuclear pumped laser in the case of low enriched uranium reactor is also possible. The use of low enriched uranium in the experiment will make experiment easier.

Obara, Toru; Takezawa, Hiroki [Center for Research into Innovative Nuclear Energy Systems Tokyo Institute of Technology 2-12-1-N1-19, Ookayama Meguro-ku, Tokyo 152-8550 (Japan)

2012-06-06T23:59:59.000Z

354

Laser studies of chemical reaction and collision processes  

SciTech Connect (OSTI)

This work has concentrated on several interrelated projects in the area of laser photochemistry and photophysics which impinge on a variety of questions in combustion chemistry and general chemical kinetics. Infrared diode laser probes of the quenching of molecules with {open_quotes}chemically significant{close_quotes} amounts of energy in which the energy transferred to the quencher has, for the first time, been separated into its vibrational, rotational, and translational components. Probes of quantum state distributions and velocity profiles for atomic fragments produced in photodissociation reactions have been explored for iodine chloride.

Flynn, G. [Columbia Univ., New York, NY (United States)

1993-12-01T23:59:59.000Z

355

Along the Laser Beampath  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

has been installed in the preamplifier modules (PAMs) at the front end of the NIF laser system. The spatial shapers can obscure the laser light at programmed locations within...

356

Laser particle sorter  

DOE Patents [OSTI]

Method and apparatus are provided for sorting particles, such as biological particles. A first laser is used to define an optical path having an intensity gradient which is effective to propel the particles along the path but which is sufficiently weak that the particles are not trapped in an axial direction. A probe laser beam is provided for interrogating the particles to identify predetermined phenotypical characteristics of the particles. A second laser beam is provided to intersect the driving first laser beam, wherein the second laser beam is activated by an output signal indicative of a predetermined characteristic. The second laser beam is switchable between a first intensity and a second intensity, where the first intensity is effective to displace selected particles from the driving laser beam and the second intensity is effective to propel selected particles along the deflection laser beam. The selected particles may then be propelled by the deflection beam to a location effective for further analysis. 2 figs.

Martin, J.C.; Buican, T.N.

1987-11-30T23:59:59.000Z

357

Laser preheat enhanced ignition  

DOE Patents [OSTI]

A method for enhancing fuel ignition performance by preheating the fuel with laser light at a wavelength that is absorbable by the fuel prior to ignition with a second laser is provided.

Early, James W. (Los Alamos, NM)

1999-01-01T23:59:59.000Z

358

Laser preheat enhanced ignition  

DOE Patents [OSTI]

A method for enhancing fuel ignition performance by preheating the fuel with laser light at a wavelength that is absorbable by the fuel prior to ignition with a second laser is provided. 11 figs.

Early, J.W.

1999-03-02T23:59:59.000Z

359

Laser-assisted electrochemistry  

SciTech Connect (OSTI)

The effect of laser irradiation on electrodeposition processes has been investigated. These studies demonstrated that the addition of laser irradiation to an electroplating process can dramatically enhance plating rates and current efficiencies, as well as improve the morphology of the resultant electrodeposit. During the course of these investigations, the mechanism for the laser enhancement of electrodeposition processes was determined. Experimental evidence was obtained to show that laser irradiation of the substrate results in increased metal ion concentrations at the surface of the electrode due to a laser-induced Soret effect. The laser-induced Soret effect has important implications for laser-assisted electrochemical processing. The increase in the surface concentration of ions allows efficient electrodeposition from dilute solutions. As such, laser- assisted electrodeposition may develop into an environmentally conscious manufacturing process by reducing waste and limiting worker exposure to toxic chemicals.

Glenn, D.F.

1995-05-01T23:59:59.000Z

360

Laser-induced damage in dielectrics with nanosecond to subpicosecond pulses. I. Experimental. Part 1  

SciTech Connect (OSTI)

The authors report extensive laser-induced damage threshold measurements on pure and multilayer dielectrics at 1053 and 526 mm for pulse durations, {tau}, ranging from 140 fs to 1 ns. Qualitative differences in the morphology of damage and a departure from the diffusion-dominated {tau}{sup 1/2} scaling indicate that damage results from plasma formation and ablation for {tau}{le}10 ps and from conventional melting and boiling for {tau}>50 ps. A theoretical model based on electron production via multiphoton ionization, Joule heating, and collisional (avalanche) ionization is in good agreement with both the pulsewidth and wavelength scaling of experimental results.

Stuart, B.C.; Herman, S.; Perry, M.D.

1994-12-01T23:59:59.000Z

Note: This page contains sample records for the topic "kinetics laser ablation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


361

Short wavelength laser  

DOE Patents [OSTI]

A short wavelength laser (28) is provided that is driven by conventional-laser pulses (30, 31). A multiplicity of panels (32), mounted on substrates (34), are supported in two separated and alternately staggered facing and parallel arrays disposed along an approximately linear path (42). When the panels (32) are illuminated by the conventional-laser pulses (30, 31), single pass EUV or soft x-ray laser pulses (44, 46) are produced.

Hagelstein, Peter L. (Livermore, CA)

1986-01-01T23:59:59.000Z

362

Laser Heat Treatment [Laser Applications Laboratory] - Nuclear Engineering  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Heat Treatment Heat Treatment Capabilities Engineering Experimentation Reactor Safety Experimentation Aerosol Experiments System Components Laser Applications Overview Laser Oil & Gas Well Drilling Laser Heat Treatment Laser Welding of Metals On-line Monitoring Laser Beam Delivery Laser Glazing of Railroad Rails High Power Laser Beam Delivery Decontamination and Decommissioning Refractory Alloy Welding Robots Applications Other Facilities Other Capabilities Work with Argonne Contact us For Employees Site Map Help Join us on Facebook Follow us on Twitter NE on Flickr Laser Applications Laboratory Laser Heat Treatment Project description: Optimization of laser beam heat treatment. Category: Project with industrial partner (Caterpillar and USCAR) Bookmark and Share Heat treatment optics

363

Observation and modelling of hollow multicharged ion x-ray spectra radiated by laser produced plasma  

SciTech Connect (OSTI)

The role of the highly charged hollow ions in the X-Ray emission plasma spectTa is investigated for 2 cases: (1) plasma obtained under inadiation of Ar clusters by ultrashort laser pulses and (2) Mg-plasma heated by a short-wavelength long (nanosecond) laser pulse. Experimental measurements are presented. Calculations in support of these measurements have been performed using a detailed atomic kinetics model with the ion distributions found from solution of the time-dependent rate equations.

Colgan, James P [Los Alamos National Laboratory; Abdallah, Joseph [Los Alamos National Laboratory; Faenov, A Ya [JAPAN/RUSSIA; Pikuz, T A [JAPAN/RUSSIA; Akobelev, I Yu [JAPAN/RUSSIA; Fukuda, Y [JAPAN/RUSSIA

2008-01-01T23:59:59.000Z

364

Laser-driven fusion  

Science Journals Connector (OSTI)

The use of intense laser light to bring about thermonuclear reactions in a plasma is of considerable current interest. We present detailed analytical and computational studies which show the feasibility of laser-driven fusion. The required laser technology and the presently anticipated practical difficulties are discussed in outline.

Keith A. Brueckner and Siebe Jorna

1974-04-01T23:59:59.000Z

365

Laser bottom hole assembly  

DOE Patents [OSTI]

There is provided for laser bottom hole assembly for providing a high power laser beam having greater than 5 kW of power for a laser mechanical drilling process to advance a borehole. This assembly utilizes a reverse Moineau motor type power section and provides a self-regulating system that addresses fluid flows relating to motive force, cooling and removal of cuttings.

Underwood, Lance D; Norton, Ryan J; McKay, Ryan P; Mesnard, David R; Fraze, Jason D; Zediker, Mark S; Faircloth, Brian O

2014-01-14T23:59:59.000Z

366

Innovative lasers for uranium isotope separation. [Progress report  

SciTech Connect (OSTI)

Copper vapor lasers have important applications to uranium atomic vapor laser isotope separation (AVLIS). The authors have spent the first two years of their project investigating two innovative methods of exciting/pumping copper vapor lasers which have the potential to improve the efficiency and scaling of large laser systems used in uranium isotope separation. Experimental research has focused on the laser discharge kinetics of (1) microwave, and (2) electron beam excitation/pumping of large-volume copper vapor lasers. During the first year, the experiments have been designed and constructed and initial data has been taken. During the second year these experiments have been diagnosed. Highlights of some of the second year results as well as plans for the future include the following: Microwave resonant cavity produced copper vapor plasmas at 2.45 GHz, have been investigated. A CW (0--500 W) signal heats and vaporizes the copper chloride to provide the atomic copper vapor. A pulsed (5 kW, 0.5--5kHz) signal is added to the incoming CW signal via a hybrid mixer to excite the copper states to the laser levels. An enhancement of the visible radiation has been observed during the pulsed pardon of the signal. Electrical probe measurements have been implemented on the system to verify the results of the electromagnetic model formulated last year. Laser gain measurements have been initiated with the use of a commercial copper vapor laser. Measurements of the spatial profile of the emission are also currently being made. The authors plan to increase the amount of pulsed microwave power to the system by implementing a high power magnetron. A laser cavity will be designed and added to this system.

Brake, M.L.; Gilgenbach, R.M.

1991-06-01T23:59:59.000Z

367

Comparison of three methods for control of postoperative pain in dogs after total ear canal ablation with lateral bulla osteotomy  

E-Print Network [OSTI]

This prospective study compared three methods of postoperative pain control in dogs undergoing total ear canal ablation with lateral bulla osteotomy. The hypothesis was that systemic opioids in conjunction with preoperative local nerve blocks would...

Buback, Janice Lynelle

2012-06-07T23:59:59.000Z

368

Cost effective nanostructured copper substrates prepared with ultrafast laser pulses for explosives detection using surface enhanced Raman scattering  

SciTech Connect (OSTI)

Ultrafast laser pulses induced surface nanostructures were fabricated on a copper (Cu) target through ablation in acetone, dichloromethane, acetonitrile, and chloroform. Surface morphological information accomplished from the field emission scanning electron microscopic data demonstrated the diversities of ablation mechanism in each case. Fabricated Cu substrates were utilized exultantly to investigate the surface plasmon (localized and propagating) mediated enhancements of different analytes using surface enhance Raman scattering (SERS) studies. Multiple utility of these substrates were efficiently demonstrated by collecting the SERS data of Rhodamine 6G molecule and two different secondary explosive molecules such as 5-amino-3-nitro-l,2,4-triazole and trinitrotoluene on different days which were weeks apart. We achieved significant enhancement factors of >10{sup 5} through an easily adoptable cleaning procedure.

Hamad, Syed [School of Physics, University of Hyderabad, Prof. C. R. Rao Road, Hyderabad 500046 (India); Podagatlapalli, G. Krishna; Soma, Venugopal Rao, E-mail: svrsp@uohyd.ernet.in, E-mail: soma-venu@yahoo.com [Advanced Center of Research in High Energy Materials (ACRHEM), University of Hyderabad, Prof. C. R. Rao Road, Hyderabad 500046 (India); Mohiddon, Md. Ahamad [Center for Nanotechnology, University of Hyderabad, Prof. C. R. Rao Road, Hyderabad 500046 (India)

2014-06-30T23:59:59.000Z

369

X-ray laser  

DOE Patents [OSTI]

An X-ray laser (10) that lases between the K edges of carbon and oxygen, i.e. between 44 and 23 Angstroms, is provided. The laser comprises a silicon (12) and dysprosium (14) foil combination (16) that is driven by two beams (18, 20) of intense line focused (22, 24) optical laser radiation. Ground state nickel-like dysprosium ions (34) are resonantly photo-pumped to their upper X-ray laser state by line emission from hydrogen-like silicon ions (32). The novel X-ray laser should prove especially useful for the microscopy of biological specimens.

Nilsen, Joseph (Livermore, CA)

1991-01-01T23:59:59.000Z

370

ESS 2012 Peer Review - Amber Kinetics Flywheel Energy Storage Demo - Ed Chiao, Amber Kinetics  

Broader source: Energy.gov (indexed) [DOE]

amber_kinetics amber_kinetics DOE Peer Review September 2012 Ed Chiao, CEO amber_kinetics Amber Kinetics: Our Flywheel History Start-up launched in 2009, Stanford University Cleantech Entrepreneurship class Established a technology licensing & flywheel development partnership with LLNL; Amber Kinetics identified new material & lower-cost rotor designs for commercialization Awarded a Smart Grid Energy Storage Demonstration grant award for flywheels Awarded a matching grant for development & demonstration of flywheel technology Stanford University Lawrence Livermore National Laboratory U.S. Department of Energy California Energy Commission World-class institutions | innovative, deep flywheel technology owned by Amber Amber Kinetics, Inc. - Confidential and Proprietary, All Rights Reserved

371

Ultrafast Laser Facility | Photosynthetic Antenna Research Center  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Ultrafast Laser Facility Ultrafast Laser Facility Click for an Overview of the Ultrafast Laser Facility The PARC Ultrafast Laser Facility, under the direction of Associate Director...

372

BNL | ATF Laser Safety  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

ATF Laser Safety ATF Laser Safety To be present in a secured laser area at ATF, a person must either have the required laser training, or be continuously escorted by someone who has such training: The training consists of an eye exam, BNL general laser safety lecture, and formal ATF laser familiarization. Untrained personnel should not be instructed to enter interlocked areas or be escorted into an area and left unattended. If someone without training must enter a secured area, they must be continuously escorted, and are considered spectators, which means they may not perform any work in the area. At ATF, there are 3 classes of personnel authorized to enter secured areas: Experimental operators may secure areas, perform approved experiments with beams from facility lasers (YAG + CO2) or FEL beams, and

373

Oxidation kinetics of aluminum diboride  

SciTech Connect (OSTI)

The oxidation characteristics of aluminum diboride (AlB{sub 2}) and a physical mixture of its constituent elements (Al+2B) were studied in dry air and pure oxygen using thermal gravimetric analysis to obtain non-mechanistic kinetic parameters. Heating in air at a constant linear heating rate of 10 C/min showed a marked difference between Al+2B and AlB{sub 2} in the onset of oxidation and final conversion fraction, with AlB{sub 2} beginning to oxidize at higher temperatures but reaching nearly complete conversion by 1500 C. Kinetic parameters were obtained in both air and oxygen using a model-free isothermal method at temperatures between 500 and 1000 C. Activation energies were found to decrease, in general, with increasing conversion for AlB{sub 2} and Al+2B in both air and oxygen. AlB{sub 2} exhibited O{sub 2}-pressure-independent oxidation behavior at low conversions, while the activation energies of Al+2B were higher in O{sub 2} than in air. Differences in the composition and morphology between oxidized Al+2B and AlB{sub 2} suggested that Al{sub 2}O{sub 3}B{sub 2}O{sub 3} interactions slowed Al+2B oxidation by converting Al{sub 2}O{sub 3} on aluminum particles into a Al{sub 4}B{sub 2}O{sub 9} shell, while the same Al{sub 4}B{sub 2}O{sub 9} developed a needle-like morphology in AlB{sub 2} that reduced oxygen diffusion distances and increased conversion. The model-free kinetic analysis was critical for interpreting the complex, multistep oxidation behavior for which a single mechanism could not be assigned. At low temperatures, moisture increased the oxidation rate of Al+2B and AlB{sub 2}, but both appear to be resistant to oxidation in cool, dry environments. - Graphical abstract: Isothermal kinetic data for AlB{sub 2} in air, showing a constantly decreasing activation energy with increasing conversion. Model-free analysis allowed for the calculation of global kinetic parameters despite many simultaneous mechanisms occurring concurrently. (a) Timetemperature plots, (b) conversion as a function of time, (c) Arrhenius plots used to calculate activation energies, and (d) activation energy as a function of conversion. Display Omitted - Highlights: First reported kinetic parameters for AlB{sub 2} and Al+2B oxidation in air and O{sub 2}. Possible mechanism of enhanced boron combustion presented. Moisture sensitivity shown to be problematic for AlB{sub 2}, less for Al+2B.

Whittaker, Michael L., E-mail: michaelwhittaker2016@u.northwestern.edu [Department of Materials Science and Engineering, University of Utah, 122S. Central Campus Drive, Salt Lake City, UT 84112 (United States); Sohn, H.Y. [Department of Metallurgical Engineering, University of Utah, 135S 1460 E, Rm 00412, Salt Lake City, UT 84112 (United States); Cutler, Raymond A. [Ceramatec, Inc., 2425S. 900W., Salt Lake City, UT 84119 (United States)

2013-11-15T23:59:59.000Z

374

Laser-induced ignition modeling of HMX  

Science Journals Connector (OSTI)

Abstract The laser-induced ignition response of HMX has been investigated using a detailed numerical model. The model is one-dimensional, fully transient, and solves the conservation equations for both the condensed and gas phases. The condensed phase representation includes radiation absorption, solid-phase transitions, melting, evaporation, and distributed semi-global decomposition kinetics. The gas phase utilizes a detailed kinetic mechanism to predict species formation and destruction. Ignition occurs in the gas phase and the flame propagates back toward the surface of the HMX in what is known as the snap-back effect. The model then transitions to steady-state combustion. Calculations were performed in which the solid HMX is irradiated with heat fluxes ranging from 50 to 1600W/cm2. Results are compared to empirical data for the laser-induced ignition of HMX. Good agreement with these data and other steady-state data (burning rate, surface temperature, melt thickness) provide the necessary validation of the developed model.

Karl V. Meredith; Matthew L. Gross; Merrill W. Beckstead

2014-01-01T23:59:59.000Z

375

A Comparison of Direct Heating During Radiofrequency and Microwave Ablation in Ex Vivo Liver  

SciTech Connect (OSTI)

This study was designed to determine the magnitude and spatial distribution of temperature elevations when using 480 kHz RF and 2.45 GHz microwave energy in ex vivo liver models. A total of 60 heating cycles (20 s at 90 W) were performed in normal, RF-ablated, and microwave-ablated liver tissues (n = 10 RF and n = 10 microwave in each tissue type). Heating cycles were performed using a 480-kHz generator and 3-cm cooled-tip electrode (RF) or a 2.45-GHz generator and 14-gauge monopole (microwave) and were designed to isolate direct heating from each energy type. Tissue temperatures were measured by using fiberoptic thermosensors 5, 10, and 15 mm radially from the ablation applicator at the depth of maximal heating. Power delivered, sensor location, heating rates, and maximal temperatures were compared using mixed effects regression models. No significant differences were noted in mean power delivered or thermosensor locations between RF and microwave heating groups (P > 0.05). Microwaves produced significantly more rapid heating than RF at 5, 10, and 15 mm in normal tissue (3.0 vs. 0.73, 0.85 vs. 0.21, and 0.17 vs. 0.09 Degree-Sign C/s; P < 0.05); and at 5 and 10 mm in ablated tissues (2.3 {+-} 1.4 vs. 0.7 {+-} 0.3, 0.5 {+-} 0.3 vs. 0.2 {+-} 0 Degree-Sign C/s, P < 0.05). The radial depth of heating was {approx}5 mm greater for microwaves than RF. Direct heating obtained with 2.45-GHz microwave energy using a single needle-like applicator is faster and covers a larger volume of tissue than 480-kHz RF energy.

Andreano, Anita; Brace, Christopher L., E-mail: clbrace@wisc.edu [University of Wisconsin, Department of Radiology (United States)

2013-04-15T23:59:59.000Z

376

Ablative Stabilization of the Deceleration-Phase Rayleigh-Taylor Instability, control No. 2000-107  

SciTech Connect (OSTI)

The growth rates of the deceleration-phase Rayleigh-Taylor instability for imploding inertial confinement fusion capsules are calculated and compared with the results of numerical simulations. It is found that the unstable spectrum and the growth rates are significantly reduced by the finite ablation flow at the shell's inner surface. For typical direct-drive capsules designed for the National Ignition Facility, the unstable spectrum exhibits a cutoff for {ell} {approx} 90.

Lobatchev, V.; Betti, R.

2000-10-01T23:59:59.000Z

377

Kinetic Modeling of Microbiological Processes  

SciTech Connect (OSTI)

Kinetic description of microbiological processes is vital for the design and control of microbe-based biotechnologies such as waste water treatment, petroleum oil recovery, and contaminant attenuation and remediation. Various models have been proposed to describe microbiological processes. This editorial article discusses the advantages and limiation of these modeling approaches in cluding tranditional, Monod-type models and derivatives, and recently developed constraint-based approaches. The article also offers the future direction of modeling researches that best suit for petroleum and environmental biotechnologies.

Liu, Chongxuan; Fang, Yilin

2012-09-17T23:59:59.000Z

378

Internal distribution of Li and B in serpentinites from the Feather River Ophiolite, California, based on laser ablation  

E-Print Network [OSTI]

silicates, such as serpentines, brucites, talc, and chlorites [Evans, 1977; Seyfried and Dibble, 1980

Lee, Cin-Ty Aeolus

379

Evaluation of pneumatic nebulization and ns-laser ablation ICP-MS for bulk elemental analysis and 2-dimensional  

E-Print Network [OSTI]

ID: JA-ART-12-2013-050387 Article Type: Paper Date Submitted by the Author: 12-Dec-2013 Complete List Brussels, Belgium.25 Electronic Supplementary Information (ESI) available Introduction The continuously

Claeys, Philippe

380

UV-Laser-Ablation-Combustion-GC-IRMS a tool for on-line analysis of intra-annual  

E-Print Network [OSTI]

it is combusted to CO2 at 700 C. Inside the reactor an oxidized copper wire provides the oxygen for the combustion (analyst) document measuring direction (analyst) high resolution post-analysis photographs for relating a high level of congruity. A conservative estimate of the precision is ± 0.24 . Comparison with a more

Note: This page contains sample records for the topic "kinetics laser ablation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


381

Laser system using ultra-short laser pulses  

DOE Patents [OSTI]

A laser system using ultrashort laser pulses is provided. In another aspect of the present invention, the system includes a laser, pulse shaper and detection device. A further aspect of the present invention employs a femtosecond laser and binary pulse shaping (BPS). Still another aspect of the present invention uses a laser beam pulse, a pulse shaper and a SHG crystal.

Dantus, Marcos (Okemos, MI); Lozovoy, Vadim V. (Okemos, MI); Comstock, Matthew (Milford, MI)

2009-10-27T23:59:59.000Z

382

Electroerosion resistance and structural phase transformations in electrospark and laser deposition of titanium alloys using composite ceramics based on ZrB2-ZrSi2 and TiN-Cr3C2 systems  

Science Journals Connector (OSTI)

The paper examines the mass transfer kinetics, structure, phase and chemical compositions, and micromechanical properties of electrospark and laser coatings on titanium alloys (including...2-ZrSi2 and TiN-Cr3C2 s...

I. A. Podchernyaeva; A. D. Panasyuk

2008-01-01T23:59:59.000Z

383

CLEERS Coordination & Development of Catalyst Process Kinetic...  

Broader source: Energy.gov (indexed) [DOE]

Development of Catalyst Process Kinetic Data - Pres. 1: Coordination of CLEERS Project; Pres. 2: ORNL Research on LNT Sulfation & Desulfation CLEERS Coordination & Development of...

384

CLEERS Coordination & Development of Catalyst Process Kinetic...  

Broader source: Energy.gov (indexed) [DOE]

& coordinate DOE research efforts (CLEERS Coordination) * Develop detailed technical data required to simulate energy efficient emission controls (LNT & SCR Kinetics, Sulfur &...

385

The Fractional Kinetic Equation and Thermonuclear Functions  

E-Print Network [OSTI]

The paper discusses the solution of a simple kinetic equation of the type used for the computation of the change of the chemical composition in stars like the Sun. Starting from the standard form of the kinetic equation it is generalized to a fractional kinetic equation and its solutions in terms of H-functions are obtained. The role of thermonuclear functions, which are also represented in terms of G- and H-functions, in such a fractional kinetic equation is emphasized. Results contained in this paper are related to recent investigations of possible astrophysical solutions of the solar neutrino problem.

H. J. Haubold; A. M. Mathai

2000-01-16T23:59:59.000Z

386

Kinetics of actinide complexation reactions  

SciTech Connect (OSTI)

Though the literature records extensive compilations of the thermodynamics of actinide complexation reactions, the kinetics of complex formation and dissociation reactions of actinide ions in aqueous solutions have not been extensively investigated. In light of the central role played by such reactions in actinide process and environmental chemistry, this situation is somewhat surprising. The authors report herein a summary of what is known about actinide complexation kinetics. The systems include actinide ions in the four principal oxidation states (III, IV, V, and VI) and complex formation and dissociation rates with both simple and complex ligands. Most of the work reported was conducted in acidic media, but a few address reactions in neutral and alkaline solutions. Complex formation reactions tend in general to be rapid, accessible only to rapid-scan and equilibrium perturbation techniques. Complex dissociation reactions exhibit a wider range of rates and are generally more accessible using standard analytical methods. Literature results are described and correlated with the known properties of the individual ions.

Nash, K.L.; Sullivan, J.C.

1997-09-01T23:59:59.000Z

387

Combustion kinetics and reaction pathways  

SciTech Connect (OSTI)

This project is focused on the fundamental chemistry of combustion. The overall objectives are to determine rate constants for elementary reactions and to elucidate the pathways of multichannel reactions. A multitechnique approach that features three independent experiments provides unique capabilities in performing reliable kinetic measurements over an exceptionally wide range in temperature, 300 to 2500 K. Recent kinetic work has focused on experimental studies and theoretical calculations of the methane dissociation system (CH{sub 4} + Ar {yields} CH{sub 3} + H + Ar and H + CH{sub 4} {yields} CH{sub 3} + H{sub 2}). Additionally, a discharge flow-photoionization mass spectrometer (DF-PIMS) experiment is used to determine branching fractions for multichannel reactions and to measure ionization thresholds of free radicals. Thus, these photoionization experiments generate data that are relevant to both reaction pathways studies (reaction dynamics) and fundamental thermochemical research. Two distinct advantages of performing PIMS with high intensity, tunable vacuum ultraviolet light at the National Synchrotron Light Source are high detection sensitivity and exceptional selectivity in monitoring radical species.

Klemm, R.B.; Sutherland, J.W. [Brookhaven National Laboratory, Upton, NY (United States)

1993-12-01T23:59:59.000Z

388

LASER SAFETY POLICY Policy Statement  

E-Print Network [OSTI]

LASER SAFETY POLICY Policy Statement Each department that acquires or operates lasers for use in laboratories or research is responsible for reporting laser acquisition to the Office of Laboratory Safety, selecting a departmental deputy laser safety officer, mandating training for its laser operators

Vertes, Akos

389

OMEGA Extended Performance Laser System  

E-Print Network [OSTI]

at UR-LLE is close to that required for ignition to occur. #12;The OMEGA Extended Performance (EP) laserOMEGA Extended Performance Laser System R. L. McCrory University of Rochester Laboratory for Laser­18 February 2008 #12;OMEGA Extended Performance Laser System R.L. McCrory Laboratory for Laser Energetics

390

Laser Safety Inspection Criteria  

SciTech Connect (OSTI)

A responsibility of the Laser Safety Officer (LSO) is to perform laser safety audits. The American National Standard Z136.1 Safe use of Lasers references this requirement in several sections: (1) Section 1.3.2 LSO Specific Responsibilities states under Hazard Evaluation, ''The LSO shall be responsible for hazards evaluation of laser work areas''; (2) Section 1.3.2.8, Safety Features Audits, ''The LSO shall ensure that the safety features of the laser installation facilities and laser equipment are audited periodically to assure proper operation''; and (3) Appendix D, under Survey and Inspections, it states, ''the LSO will survey by inspection, as considered necessary, all areas where laser equipment is used''. Therefore, for facilities using Class 3B and or Class 4 lasers, audits for laser safety compliance are expected to be conducted. The composition, frequency and rigueur of that inspection/audit rests in the hands of the LSO. A common practice for institutions is to develop laser audit checklists or survey forms. In many institutions, a sole Laser Safety Officer (LSO) or a number of Deputy LSO's perform these audits. For that matter, there are institutions that request users to perform a self-assessment audit. Many items on the common audit list and the associated findings are subjective because they are based on the experience and interest of the LSO or auditor in particular items on the checklist. Beam block usage is an example; to one set of eyes a particular arrangement might be completely adequate, while to another the installation may be inadequate. In order to provide more consistency, the National Ignition Facility Directorate at Lawrence Livermore National Laboratory (NIF-LLNL) has established criteria for a number of items found on the typical laser safety audit form. These criteria are distributed to laser users, and they serve two broad purposes: first, it gives the user an expectation of what will be reviewed by an auditor, and second, it is an opportunity to explain audit items to the laser user and thus the reasons for some of these items. Some examples are given from the audit criteria handout. As an explanatory key to the reader, an Operational Safety Procedure (OSP) as a formally reviewed safety procedure required for all Class 3B and Class 4 laser installations. An ''OSP Binder'' contains all safety documentation related to a given laser operation and serves as a central repository for documents, such as the OSP, interlock logs, lessons learned, contact information etc. ''Unattended Operation'' refers to approved procedures for unattended operation of the laser installation and may include operation beyond normal working hours. ''L-train'' is the LLNL training tracking system.

Barat, K

2005-02-11T23:59:59.000Z

391

Multiple temperature kinetic model and gas-kinetic method for hypersonic non-equilibrium flow computations  

E-Print Network [OSTI]

Multiple temperature kinetic model and gas-kinetic method for hypersonic non-equilibrium flow. For the non-equilibrium flow computations, i.e., the nozzle flow and hypersonic rarefied flow over flat plate-kinetic method; Hypersonic and rarefied flows 1. Introduction The development of aerospace technology has

Xu, Kun

392

Testing the kinetic energy functional: Kinetic energy density as a density functional  

E-Print Network [OSTI]

is to the exchange-correlation energy as a functional of the density. A large part of the total energy, the kinetic contexts. For finite systems these forms integrate to the same global ki- netic energy, but they differTesting the kinetic energy functional: Kinetic energy density as a density functional Eunji Sim

Burke, Kieron

393

Laser assisted high entropy alloy coating on aluminum: Microstructural evolution  

SciTech Connect (OSTI)

High entropy alloy (Al-Fe-Co-Cr-Ni) coatings were synthesized using laser surface engineering on aluminum substrate. Electron diffraction analysis confirmed the formation of solid solution of body centered cubic high entropy alloy phase along with phases with long range periodic structures within the coating. Evolution of such type of microstructure was a result of kinetics associated with laser process, which generates higher temperatures and rapid cooling resulting in retention of high entropy alloy phase followed by reheating and/or annealing in subsequent passes of the laser track giving rise to partial decomposition. The partial decomposition resulted in formation of precipitates having layered morphology with a mixture of high entropy alloy rich phases, compounds, and long range ordered phases.

Katakam, Shravana; Joshi, Sameehan S.; Mridha, Sanghita; Mukherjee, Sundeep; Dahotre, Narendra B., E-mail: Narendra.Dahotre@unt.edu [Department of Materials Science and Engineering, University of North Texas, 1150 Union Circle, 305310 Denton, Texas 76203-5017 (United States)

2014-09-14T23:59:59.000Z

394

Laser-rf creation and diagnostics of seeded atmospheric pressure air and nitrogen plasmas  

E-Print Network [OSTI]

Laser-rf creation and diagnostics of seeded atmospheric pressure air and nitrogen plasmas Siqi Luo to the ambient air. The atmospheric-pressure plasma is then maintained with the 13.56 MHz rf power. Using of atmospheric-pressure air plasmas The kinetics of reactions and transitions in atmospheric- pressure air

Scharer, John E.

395

Analysis of atomic and ion debris features of laser-produced Sn and Li plasmas  

E-Print Network [OSTI]

Analysis of atomic and ion debris features of laser-produced Sn and Li plasmas R. W. Coons,a S. S. Harilal, D. Campos, and A. Hassanein School of Nuclear Engineering and Center for Materials Under Extreme provide a CE nearly twice that of Li. However, the kinetic energies of Sn ions are considerably higher

Harilal, S. S.

396

Laser-PlasmaWakefield Acceleration with Higher Order Laser Modes  

E-Print Network [OSTI]

Design considerations for a laser-plasma linear collider,"E.Esarey, and W.P.Leemans, "Free-electron laser driven bythe LBNL laser-plasma accelerator," in Proc. Adv. Acc. Con.

Geddes, C.G.R.

2011-01-01T23:59:59.000Z

397

Laser induced nuclear reactions  

SciTech Connect (OSTI)

Dramatic improvements in laser technology since 1984 have revolutionised high power laser technology. Application of chirped-pulse amplification techniques has resulted in laser intensities in excess of 10{sup 19} W/cm{sup 2}. In the mid to late eighties, C. K. Rhodes and K. Boyer discussed the possibility of shining laser light of this intensity onto solid surfaces and to cause nuclear transitions. In particular, irradiation of a uranium target could induce electro- and photofission in the focal region of the laser. In this paper it is shown that {mu}Ci of {sup 62}Cu can be generated via the ({gamma},n) reaction by a laser with an intensity of about 10{sup 19} Wcm{sup -2}.

Ledingham, Ken; McCanny, Tom; Graham, Paul; Fang Xiao; Singhal, Ravi; Magill, Joe; Creswell, Alan; Sanderson, David; Allott, Ric; Neely, David; Norreys, Peter; Santala, Marko; Zepf, Matthew; Watts, Ian; Clark, Eugene; Krushelnick, Karl; Tatarakis, Michael; Dangor, Bucker; Machecek, Antonin; Wark, Justin [Department of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, Scotland (United Kingdom); European Commission, Institute for Transuranic Elements, Karlsruhe, Postfach 2340, D-76125 (Germany); Scottish Universities Research and Reactor Centre, East Kilbride, Glasgow G75 0QU (United Kingdom); Rutherford Appleton Laboratory, Chilton, Didcot (United Kingdom); Blackett Laboratory, Imperial College, London SW7 2BZ (United Kingdom); Clarendon Laboratory, Department of Physics, University of Oxford, OX1 3PU (United Kingdom)

1998-12-16T23:59:59.000Z

398

Polarization feedback laser stabilization  

DOE Patents [OSTI]

A system for locking two Nd:YAG laser oscillators includes an optical path for feeding the output of one laser into the other with different polarizations. Elliptical polarization is incorporated into the optical path so that the change in polarization that occurs when the frequencies coincide may be detected to provide a feedback signal to control one laser relative to the other. 4 figs.

Esherick, P.; Owyoung, A.

1987-09-28T23:59:59.000Z

399

The effects of early time laser drive on hydrodynamic instability growth in National Ignition Facility implosions  

SciTech Connect (OSTI)

Defects on inertial confinement fusion capsule surfaces can seed hydrodynamic instability growth and adversely affect capsule performance. The dynamics of shocks launched during the early period of x-ray driven National Ignition Facility (NIF) implosions determine whether perturbations will grow inward or outward at peak implosion velocity and final compression. In particular, the strength of the first shock, launched at the beginning of the laser pulse, plays an important role in determining Richtmyer-Meshkov (RM) oscillations on the ablation front. These surface oscillations can couple to the capsule interior through subsequent shocks before experiencing Rayleigh-Taylor (RT) growth. We compare radiation hydrodynamic simulations of NIF implosions to analytic theories of the ablative RM and RT instabilities to illustrate how early time laser strength can alter peak velocity growth. We develop a model that couples the RM and RT implosion phases and captures key features of full simulations. We also show how three key parameters can control the modal demarcation between outward and inward growth.

Peterson, J. L.; Clark, D. S.; Suter, L. J. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Masse, L. P. [CEA, DAM, DIF, 91297 Arpajon (France)

2014-09-15T23:59:59.000Z

400

Terahertz Quantum Cascade Lasers  

Science Journals Connector (OSTI)

We provide an overview of terahertz quantum cascade lasers based on resonant-phonon depopulation and metal-metal waveguides, including two-phonon resonant-phonon depopulation...

Williams, Benjamin; Kumar, Sushil; Qin, Qi; Lee, Alan Wei Min; Hu, Qing; Reno, John L; Wasilewski, Z R; Liu, H C

Note: This page contains sample records for the topic "kinetics laser ablation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

Kinetic and mechanistic studies of free-radical reactions in combustion  

SciTech Connect (OSTI)

Combustion is driven by energy-releasing chemical reactions. Free radicals that participate in chain reactions carry the combustion process from reactants to products. Research in chemical kinetics enables us to understand the microscopic mechanisms involved in individual chemical reactions as well as to determine the rates at which they proceed. Both types of information are required for an understanding of how flames burn, why engines knock, how to minimize the production of pollutants, and many other important questions in combustion. In this program the authors emphasize accurate measurements over wide temperature ranges of the rates at which ubiquitous free radicals react with stable molecules. The authors investigate a variety of OH, CN, and CH + stable molecule reactions important to fuel conversion, emphasizing application of the extraordinarily precise technique of laser photolysis/continuous-wave laser-induced fluorescence (LP/cwLIF). This precision enables kinetic measurements to serve as mechanistic probes. Since considerable effort is required to study each individual reaction, prudent selection is critical. Two factors encourage selection of a specific reaction: (1) the rates and mechanisms of the subject reaction are required input to a combustion model; and (2) the reaction is a chemical prototype which, upon characterization, will provide fundamental insight into chemical reactivity, facilitate estimation of kinetic parameters for similar reactions, and constrain and test the computational limits of reaction-rate theory. Most studies performed in this project satisfy both conditions.

Tully, F.P. [Sandia National Laboratories, Livermore, CA (United States)

1993-12-01T23:59:59.000Z

402

OMEGA EP Laser Dedication Movie - Laboratory for Laser Energetics  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Dedication Movie - Laboratory for Laser Energetics Laboratory for Laser Energetics Logo Search Home Around the Lab Past Issues Past Quick Shots About Office of the Director Map to...

403

Chirped Laser Dispersion Spectroscopy with Directly Modulated Quantum Cascade Laser  

Science Journals Connector (OSTI)

A feasibility study of chirped laser dispersion spectroscopy (CLaDS) with utilizing direct modulation of a quantum cascade laser instead of external modulators is presented....

Hangauer, Andreas; Spinner, Georg; Nikodem, Michal; Wysocki, Gerard

404

Kinetic roughening on curved interfaces  

E-Print Network [OSTI]

Stochastic growth phenomena on curved interfaces have not been explored in so much detail as their planar counterparts. The independence of the interface macroscopic shape on kinetic roughening has been occasionally assumed, but however, this fact can not be considered as universal. Stochastic partial differential equations on curved interfaces present dynamical and morphological properties that are completely different from their planar equivalents. Herein we will concentrate on equations which planar counterparts are linear. The fundamental differences are the loss of correlation of the interface through time for models showing sub-ballistic propagation of the correlations and the irrelevance of the noise in two and higher dimensional settings. We analyze some of these processes in detail, exploring why these consequences arise, and show that they tend to appear irrespective of the particular metric, provided that it is not Euclidean. Models showing a super-ballistic propagation of correlations present a fl...

Escudero, Carlos

2008-01-01T23:59:59.000Z

405

Decohesion Kinetics in Polymer Organic Solar Cells  

Science Journals Connector (OSTI)

Decohesion Kinetics in Polymer Organic Solar Cells ... We investigate the role of molecular weight (MW) of the photoactive polymer poly(3-hexylthiophene) (P3HT) on the temperature-dependent decohesion kinetics of bulk heterojunction (BHJ) organic solar cells (OSCs). ... fullerenes; solar cells; thin films; fracture; polymer ...

Christopher Bruner; Fernando Novoa; Stephanie Dupont; Reinhold Dauskardt

2014-11-04T23:59:59.000Z

406

Kinetics of Non-Thermal Atmospheric Pressure  

E-Print Network [OSTI]

Kinetics of Non-Thermal Atmospheric Pressure Plasmas Alexander Fridman · Microdischarge Interaction and Structuring in Dielectric Barrier Discharges · Kinetics of Blood Coagulation in Plasma · Surface Wound wire Area of DBD plasma region: ~104cm2 #12;7 Microdischarge Patterning (2D) R22 R23 R24 R26 R27 R28

Kaganovich, Igor

407

Chemical kinetics and oil shale process design  

SciTech Connect (OSTI)

Oil shale processes are reviewed with the goal of showing how chemical kinetics influences the design and operation of different processes for different types of oil shale. Reaction kinetics are presented for organic pyrolysis, carbon combustion, carbonate decomposition, and sulfur and nitrogen reactions.

Burnham, A.K.

1993-07-01T23:59:59.000Z

408

ADVANCES IN ENVIRONMENTAL REACTION KINETICS AND THERMODYNAMICS  

E-Print Network [OSTI]

1262 ADVANCES IN ENVIRONMENTAL REACTION KINETICS AND THERMODYNAMICS: LONG-TERM FATE thermodynamic and kinetic data is available with regard to the formation of these mixed metal precipitate phases to six months from the initial addition of aqueous nickel. Additionally, we have determined thermodynamic

Sparks, Donald L.

409

Documentation - Laboratory for Laser Energetics  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Daily Securing Checklist (S-AB-P-482) EP Bay and OAA Securing Walkthrough (S-AB-P-582) Laser StartupShutdown LOTF Laser Startup (S-AB-P-038) LOTF Laser Shutdown (S-AB-P-039) IRAT...

410

Plasmonic Quantum Cascade Laser Antenna  

Science Journals Connector (OSTI)

We demonstrate the plasmonic quantum cascade laser antenna, that can confine mid-infrared radiation beyond the diffraction limit, by integrating gold optical antennas on the laser...

Yu, Nanfang; Cubukcu, Ertugrul; Diehl, Laurent; Crozier, Kenneth; Capasso, Federico

411

Chemical Kinetic Modeling of Non-Petroleum Based Fuels | Department...  

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

ft010pitz2012o.pdf More Documents & Publications Chemical Kinetic Modeling of Non-Petroleum Based Fuels Chemical Kinetic Modeling of Fuels Chemical Kinetic Research on HCCI &...

412

From Gas Lasers and Tunable Raman Lasers to Quantum Cascade Lasers  

Science Journals Connector (OSTI)

I will describe my involvement in lasers from 1961 to the present, ecompassing high power carbon dioxide lasers, tunable spin-flip Raman lasers, and now high power CW room temperature...

Patel, Kumar

413

Laser photoelectron spectroscopy of ions  

SciTech Connect (OSTI)

This enterprise uses photoelectron spectroscopy to study the properties of negative ions and radicals. The essence of our experiment is to cross a 0.6 keV mass-selected ion beam (M{sup {minus}}) with the output of a CW laser, {Dirac h}{omega}{sub o}. The resultant detached photoelectrons with kinetic energy, KE, are energy analyzed by means of a set of electrostatic hemispherical analyzers. Analysis of the photoelectron spectra enables us to extract molecular electron affinities, vibrational frequencies and electronic splittings of the final radical, M, as well as the relative molecular geometries of ions (M{sup {minus}}) and radicals (M). We have scrutinized the two simplest nitrenes: methylnitrene (CH{sub 3}N) and phenylnitrene (C{sub 6}H{sub 5}N). By preparing the corresponding anions, CH{sub 3}N{sup {minus}} and C{sub 6}H{sub 5}N{sup {minus}}, we have studied these nitrene biradicals. Singlet methylnitrene is especially interesting since it is formally a transition state.''

Ellison, G.B.

1992-01-16T23:59:59.000Z

414

Liquid heat capacity lasers  

DOE Patents [OSTI]

The heat capacity laser concept is extended to systems in which the heat capacity lasing media is a liquid. The laser active liquid is circulated from a reservoir (where the bulk of the media and hence waste heat resides) through a channel so configured for both optical pumping of the media for gain and for light amplification from the resulting gain.

Comaskey, Brian J. (Walnut Creek, CA); Scheibner, Karl F. (Tracy, CA); Ault, Earl R. (Livermore, CA)

2007-05-01T23:59:59.000Z

415

Explosively pumped laser light  

DOE Patents [OSTI]

A single shot laser pumped by detonation of an explosive in a shell casing. The shock wave from detonation of the explosive causes a rare gas to luminesce. The high intensity light from the gas enters a lasing medium, which thereafter outputs a pulse of laser light to disable optical sensors and personnel.

Piltch, Martin S. (Los Alamos, NM); Michelotti, Roy A. (Los Alamos, NM)

1991-01-01T23:59:59.000Z

416

Temporal Trends in the Histology of the Rabbit Kidney after Cavitational Tissue Ablation  

Science Journals Connector (OSTI)

Tissue can be mechanically ablated through inertial cavitation generated by high intensity pulsed ultrasound. The ablation appears acutely as a fine slurry with absent cellular structure. Long?term effects and the evolution of histologic changes in disrupted tissue remain poorly understood. This study aimed to characterize the 060 day histology of cavitational ablation in a rabbit model. 29 New Zealand White rabbits were anesthetized and exposed to high intensity pulses of ultrasound (60000 pulses 20 usec duration 750 kHz 1 kHz PRF 18 MPa peak rarefactional pressure lower pole left kidney). Kidneys were harvested immediately from five rabbits. The others were recovered and the kidneys were harvested 1 2 7 20 or 60 days after treatment. Grossly kidneys from 02 days displayed subcapsular bruising near the exposure site and some hemorrhage in the adjacent perirenal fat; microscopically a disrupted acellular zone measuring 35 mm by 510 mm accompanied by local infiltration of neutrophils (acute inflammation) was seen. Kidneys harvested after 7 days displayed tubular dilatation adjacent to the targeted area and collagen deposition consistent with scar formation. Decreased collagen deposition decreased size of the disrupted zone and regeneration of the tubular basal cell layer of dilated tubules was evident by day 20. Kidneys harvested at 20 and 60 days had contour defects near the exposure site with an apparent volume loss. Cavitation causes orderly and predictable histologic changes. Local renal damage induced during histotripsy may be partially reversible. Further research is needed to identify the clinical correlates of the observed histologic findings.

Timothy L. Hall; Kathleen Kieran; J. Brian Fowlkes; Charles A. Cain; William W. Roberts

2007-01-01T23:59:59.000Z

417

Radiofrequency Ablation of Large Renal Angiomyolipoma: Median-Term Follow-Up  

SciTech Connect (OSTI)

Purpose. To study the feasibility of percutaneous radiofrequency ablation (RFA) of large angiomyolipomas (AMLs) using saline-cooled electrodes. Materials and Methods. Institutional Review Board approval for the study was received. Four patients (all female, age range 33-67 years) with large AMLs (maximal axis 6.1-32.4 cm) not suitable for embolotherapy or surgery consented to a trial of RFA. Procedures were performed under computerized tomographic guidance using 14G saline-infused electrodes. Two ablations (diameter 4-7 cm) were undertaken in each patient. Variables studied were technical success, treatment safety, alteration of tumor consistency, tumor size, effect on renal function, and medium-term freedom from haemorrhage. Results. All four patients underwent successful RFA without any intraprocedural complications. There has been no haemorrhage, or new renal specific symptom, during a minimum 48-month period, and normal renal function has been normal. On follow-up radiological imaging, the tumors have become fattier with involution of the soft-tissue elements (soft tissue-to-total tumor ratio decreased mean [range] of 0.26 [0.14-0.48] to 0.17 [0.04-0.34] U; p = 0.04 [paired Student t test]). Further evidence of treatment effect was the development of a capsule around the ablation zone, but there was no change in overall tumor volume (mean [range] 1,120 [118-2,845] to 1150 [90-3,013] ml; p = 1 [paired Student t test]). Conclusion. RFA of large AMLs is technically feasible using saline-infused electrodes. The soft-tissue elements decreased in volume; the tumors become fattier; and there has been no renal haemorrhage during a 48-month period.

Gregory, S. M., E-mail: drstephengregory@gmail.com; Anderson, C. J.; Patel, U. [St. George's Hospital and Medical School, Department of Radiology (United Kingdom)

2013-06-15T23:59:59.000Z

418

Direct Visualization of Initial SEI Morphology and Growth Kinetics...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Initial SEI Morphology and Growth Kinetics During Lithium Deposition by in situ Electrochemical Direct Visualization of Initial SEI Morphology and Growth Kinetics During Lithium...

419

Transport-controlled kinetics of dissolution and precipitation...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Transport-controlled kinetics of dissolution and precipitation in the sediments under alkaline and saline conditions . Transport-controlled kinetics of dissolution and...

420

Studying The Kinetics Of Crystalline Silicon Nanoparticle Lithiation...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Studying The Kinetics Of Crystalline Silicon Nanoparticle Lithiation With In-Situ Transmission Electron Microscopy. Studying The Kinetics Of Crystalline Silicon Nanoparticle...

Note: This page contains sample records for the topic "kinetics laser ablation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

Global Optimization of Chemical Reactors and Kinetic Optimization  

E-Print Network [OSTI]

Model; 3-D; Monolith; Reactor; Optimization Introduction TheAngeles Global Optimization of Chemical Reactors and KineticGlobal Optimization of Chemical Reactors and Kinetic

ALHUSSEINI, ZAYNA ISHAQ

2013-01-01T23:59:59.000Z

422

Structure, Kinetics, and Thermodynamics of the Aqueous Uranyl...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Kinetics, and Thermodynamics of the Aqueous Uranyl(VI) Cation. Structure, Kinetics, and Thermodynamics of the Aqueous Uranyl(VI) Cation. Abstract: Molecular simulation techniques...

423

Microscale Electrode Design Using Coupled Kinetic, Thermal and...  

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

Microscale Electrode Design Using Coupled Kinetic, Thermal and Mechanical Modeling Microscale Electrode Design Using Coupled Kinetic, Thermal and Mechanical Modeling 2010 DOE...

424

Microscale Electrode Design Using Coupled Kinetic, Thermal and...  

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

Microscale Electrode Design Using Coupled Kinetic, Thermal and Mechanical Modeling Microscale Electrode Design Using Coupled Kinetic, Thermal and Mechanical Modeling 2009 DOE...

425

Coupled Kinetic, Thermal, and Mechanical Modeling of FIB Micro...  

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

Coupled Kinetic, Thermal, and Mechanical Modeling of FIB Micro-machined Electrodes Coupled Kinetic, Thermal, and Mechanical Modeling of FIB Micro-machined Electrodes 2010 DOE...

426

Benchmark Reaction Mechanisms and Kinetics for Lean NOx Traps...  

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

Benchmark Reaction Mechanisms and Kinetics for Lean NOx Traps Development of Chemical Kinetic Models for Lean NOx Traps Modeling the Regeneration Chemistry of Lean NOx Traps...

427

Experimentally determined dissolution kinetics of Na-rich borosilicate...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Experimentally determined dissolution kinetics of Na-rich borosilicate glass at far from equilibrium conditions: Implications Experimentally determined dissolution kinetics of...

428

Laser dividing apparatus  

DOE Patents [OSTI]

A laser beam dividing apparatus (10) having a first beam splitter (14) with an aperture (16) therein positioned in the path of a laser beam (12) such that a portion of the laser beam (12) passes through the aperture (16) onto a second beam splitter (20) and a portion of the laser beam (12) impinges upon the first beam splitter (14). Both the first beam splitter (14) and the second beam splitter (20) are, optionally, made from a dichroic material such that a green component (24) of the laser beam (12) is reflected therefrom and a yellow component (26) is refracted therethrough. The first beam splitter (14) and the second beam splitter (20) further each have a plurality of facets (22) such that the components (24, 26) are reflected and refracted in a number equaling the number of facets (22).

English, Jr., R. Edward (Tracy, CA); Johnson, Steve A. (Tracy, CA)

1995-01-01T23:59:59.000Z

429

Guest Editorial: Laser Damage  

SciTech Connect (OSTI)

Laser damage of optical materials, first reported in 1964, continues to limit the output energy and power of pulsed and continuous-wave laser systems. In spite of some 48 years of research in this area, interest from the international laser community to laser damage issues remains at a very high level and does not show any sign of decreasing. Moreover, it grows with the development of novel laser systems, for example, ultrafast and short-wavelength lasers that involve new damage effects and specific mechanisms not studied before. This interest is evident from the high level of attendance and presentations at the annual SPIE Laser Damage Symposium (aka, Boulder Damage Symposium) that has been held in Boulder, Colorado, since 1969. This special section of Optical Engineering is the first one devoted to the entire field of laser damage rather than to a specific part. It is prepared in response to growing interest from the international laser-damage community. Some papers in this special section were presented at the Laser Damage Symposium; others were submitted in response to the general call for papers for this special section. The 18 papers compiled into this special section represent many sides of the broad field of laser-damage research. They consider theoretical studies of the fundamental mechanisms of laser damage including laser-driven electron dynamics in solids (O. Brenk and B. Rethfeld; A. Nikiforov, A. Epifanov, and S. Garnov; T. Apostolova et al.), modeling of propagation effects for ultrashort high-intensity laser pulses (J. Gulley), an overview of mechanisms of inclusion-induced damage (M. Koldunov and A. Manenkov), the formation of specific periodic ripples on a metal surface by femtosecond laser pulses (M. Ahsan and M. Lee), and the laser-plasma effects on damage in glass (Y. Li et al). Material characterization is represented by the papers devoted to accurate and reliable measurements of absorption with special emphasis on thin films (C. Mhlig and S. Bublitz; B. Cho, E. Danielewicz, and J. Rudisill; W. Palm et al; and J. Lu et al.). Statistical treatment of measurements of the laser-damage threshold (J. Arenberg) and the relationship to damage mechanisms (F. Wagner et al.) represent the large subfield of laser-damage measurements. Various aspects of multilayer coating and thin-film characterization are considered in papers by B. Cho, J. Rudisill, and E. Danielewicz (spectral shift in multilayer mirrors) and R. Weber et al. (novel approach to damage studies based on third-harmonic generation microscopy). Of special interest for readers is the paper by C. Stolz that summarizes the results of four thin-film damage competitions organized as a part of the Laser Damage Symposium. Another paper is devoted to thermal annealing of damage precursors (N. Shen et al.). Finally, the influence of nano-size contamination on initiation of laser damage by ultrashort pulses is considered in paper of V. Komolov et al.

Vitaly Gruzdev, Michelle D. Shinn

2012-12-01T23:59:59.000Z

430

Laser irradiation effects on the CdTe/ZnTe quantum dot structure studied by Raman and AFM spectroscopy  

SciTech Connect (OSTI)

Micro-Raman spectroscopy has been applied to investigate the impact of laser irradiation on semiconducting CdTe/ZnTe quantum dots (QDs) structures. A reference sample (without dots) was also studied for comparison. Both samples were grown by molecular beam epitaxy technique on the p-type GaAs substrate. The Raman spectra have been recorded for different time of a laser exposure and for various laser powers. The spectra for both samples exhibit peak related to the localized longitudinal (LO) ZnTe phonon of a wavenumber equal to 210 cm{sup -1}. For the QD sample, a broad band corresponding to the LO CdTe phonon related to the QD-layer appears at a wavenumber of 160 cm{sup -1}. With increasing time of a laser beam exposure and laser power, the spectra get dominated by tellurium-related peaks appearing at wavenumbers around 120 cm{sup -1} and 140 cm{sup -1}. Simultaneously, the ZnTe surface undergoes rising damage, with the formation of Te aggregates at the pinhole edge as reveal atomic force microscopy observations. Local temperature of irradiated region has been estimated from the anti-Stokes/Stokes ratio of the Te modes intensity and it was found to be close or exceeding ZnTe melting point. Thus, the laser damage can be explained by the ablation process.

Zielony, E.; Placzek-Popko, E.; Henrykowski, A.; Gumienny, Z.; Kamyczek, P.; Jacak, J. [Institute of Physics, Wroclaw University of Technology, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw (Poland); Nowakowski, P.; Karczewski, G. [Institute of Physics, Polish Academy of Sciences, al. Lotnikow 32/46, 02-668 Warsaw (Poland)

2012-09-15T23:59:59.000Z

431

Interferometric and schlieren characterization of the plasmas and shock wave dynamics during laser-triggered discharge in atmospheric air  

SciTech Connect (OSTI)

This paper describes our efforts to reveal the underlying physics of laser-triggered discharges in atmospheric air using a Mach-Zehnder interferometer and schlieren photography. Unlike the hemispherical shock waves that are produced by laser ablation, bell-like morphologies are observed during laser-triggered discharges. Phase shifts are recovered from the interferograms at a time of 1000?ns by the 2D fast Fourier transform method, and then the values of the refractive index are deduced using the Abel inversion. An abundance of free electrons is expected near the cathode surface. The schlieren photographs visualize the formation of stagnation layers at ?600?ns in the interaction zones of the laser- and discharge-produced plasmas. Multiple reflected waves are observed at later times with the development of shock wave propagations. Estimations using the Taylor-Sedov self-similar solution indicated that approximately 45.8% and 51.9% of the laser and electrical energies are transferred into the gas flow motions, respectively. Finally, numerical simulations were performed, which successfully reproduced the main features of the experimental observations, and provided valuable insights into the plasma and shock wave dynamics during the laser-triggered discharge.

Wei, Wenfu; Li, Xingwen, E-mail: xwli@mail.xjtu.edu.cn; Wu, Jian; Yang, Zefeng; Jia, Shenli; Qiu, Aici [State Key Laboratory of Electrical Insulation and Power Equipment, Xi'an Jiaotong University, Shaanxi 710049 (China)

2014-08-15T23:59:59.000Z

432

The Theta Laser A Low Noise Chirped Pulse Laser  

E-Print Network [OSTI]

The Theta Laser A Low Noise Chirped Pulse Laser Dimitrios Mandridis dmandrid@creol.ucf.edu April 29, 2011 CREOL Affiliates Day 2011 #12;2 Objective: Frequency Swept (FM) Mode-locked Laser · Develop a frequency swept laser, · linear f-sweep, · uniform-intensity, · low noise, · with long-term stability

Van Stryland, Eric

433

Modeling of Reactor Kinetics and Dynamics  

SciTech Connect (OSTI)

In order to model a full fuel cycle in a nuclear reactor, it is necessary to simulate the short time-scale kinetic behavior of the reactor as well as the long time-scale dynamics that occur with fuel burnup. The former is modeled using the point kinetics equations, while the latter is modeled by coupling fuel burnup equations with the kinetics equations. When the equations are solved simultaneously with a nonlinear equation solver, the end result is a code with the unique capability of modeling transients at any time during a fuel cycle.

Matthew Johnson; Scott Lucas; Pavel Tsvetkov

2010-09-01T23:59:59.000Z

434

Quantum electrodynamics in a laser and the electron laser collision  

E-Print Network [OSTI]

Quantum electrodynamics in a laser is formulated, in which the electron-laser interaction is exactly considered, while the interaction of an electron and a single photon is considered by perturbation. The formulation is applied to the electron-laser collisions. The effect of coherence between photons in the laser is therefore fully considered in these collisions. The possibility of $\\gamma-$ray laser generation by use of this kind of collision is discussed.

Qi-Ren Zhang

2014-08-08T23:59:59.000Z

435

Ultra-fast laser system  

DOE Patents [OSTI]

A laser system is provided which selectively excites Raman active vibrations in molecules. In another aspect of the present invention, the system includes a laser, pulse shaper and detection device. A further aspect of the present invention employs a femtosecond laser and binary pulse shaping (BPS). Still another aspect of the present invention uses a laser beam pulse, a pulse shaper and remote sensing.

Dantus, Marcos; Lozovoy, Vadim V

2014-01-21T23:59:59.000Z

436

1982 laser program annual report  

SciTech Connect (OSTI)

This annual report covers the following eight sections: (1) laser program review, (2) laser systems and operation, (3) target design, (4) target fabrication, (5) fusion experiments program, (6) Zeus laser project, (7) laser research and development, and (8) energy applications. (MOW)

Hendricks, C.D.; Grow, G.R. (eds.)

1983-08-01T23:59:59.000Z

437

Kinetics of Two-Photon Absorption from Metastable Defect Levels in Solids  

Science Journals Connector (OSTI)

The results of two-photon absorption from metastable defect levels are presented in terms of a wide range of the characteristic trapping parameters of a simple model of a solid. The instantaneous photocurrent maxima and the luminescence brightness maxima as obtained from exact solutions of the coupled nonlinear kinetic equations are shown to depend on the square of the laser flux, provided that the intensity is a few orders of magnitude smaller than the laserdamage threshold. The square-law dependence is lost close to the threshold. These results are independent of surface recombination and diffusion.

Paul Kelly and Peter Brunlich

1971-03-15T23:59:59.000Z

438

Stereotactic Ablative Body Radiation Therapy for Octogenarians With Non-Small Cell Lung Cancer  

SciTech Connect (OSTI)

Purpose: To retrospectively investigate treatment outcomes of stereotactic ablative body radiation therapy (SABR) for octogenarians with non-small cell lung cancer (NSCLC). Methods and Materials: Between 2005 and 2012, 109 patients aged ?80 years with T1-2N0M0 NSCLC were treated with SABR: 47 patients had histology-unproven lung cancer; 62 patients had pathologically proven NSCLC. The prescribed doses were either 50 Gy/5 fractions for peripheral tumors or 40 Gy/5 fractions for centrally located tumors. The treatment outcomes, toxicities, and the correlating factors for overall survival (OS) were evaluated. Results: The median follow-up duration after SABR was 24.2 (range, 3.0-64.6) months. Only limited toxicities were observed, except for 1 grade 5 radiation pneumonitis. The 3-year local, regional, and distant metastasis-free survival rates were 82.3%, 90.1%, and 76.8%, respectively. The OS and lung cancer-specific survival rates were 53.7% and 70.8%, respectively. Multivariate analysis revealed that medically inoperable, low body mass index, high T stage, and high C-reactive protein were the predictors for short OS. The OS for the operable octogenarians was significantly better than that for inoperable (P<.01). Conclusions: Stereotactic ablative body radiation therapy for octogenarians was feasible, with excellent OS. Multivariate analysis revealed that operability was one of the predictors for OS. For medically operable octogenarians with early-stage NSCLC, SABR should be prospectively compared with resection.

Takeda, Atsuya; Sanuki, Naoko; Eriguchi, Takahisa [Radiation Oncology Center, Ofuna Chuo Hospital, Kanagawa (Japan)] [Radiation Oncology Center, Ofuna Chuo Hospital, Kanagawa (Japan); Kaneko, Takeshi [Respiratory Disease Center, Yokohama City University Medical Center, Kanagawa (Japan) [Respiratory Disease Center, Yokohama City University Medical Center, Kanagawa (Japan); Department of Respirology, Ofuna Chuo Hospital, Kanagawa (Japan); Morita, Satoshi [Department of Biostatistics and Epidemiology, Graduate School of Medicine, Yokohama City University, Kanagawa (Japan)] [Department of Biostatistics and Epidemiology, Graduate School of Medicine, Yokohama City University, Kanagawa (Japan); Handa, Hiroshi [Respiratory Disease Center, Yokohama City University Medical Center, Kanagawa (Japan) [Respiratory Disease Center, Yokohama City University Medical Center, Kanagawa (Japan); Division of Respiratory and Infectious Diseases, Department of Internal Medicine, St. Marianna University School of Medicine, Kanagawa (Japan); Aoki, Yousuke; Oku, Yohei [Radiation Oncology Center, Ofuna Chuo Hospital, Kanagawa (Japan)] [Radiation Oncology Center, Ofuna Chuo Hospital, Kanagawa (Japan); Kunieda, Etsuo, E-mail: kunieda-mi@umin.ac.jp [Department of Radiation Oncology, Tokai University, Kanagawa (Japan)] [Department of Radiation Oncology, Tokai University, Kanagawa (Japan)

2013-06-01T23:59:59.000Z

439

Kinetic equilibrium reconstruction on EAST tokamak  

Science Journals Connector (OSTI)

Plasma equilibrium is an important basis for tokamak plasma research. The equilibrium reconstructed from experimental diagnostics is a key element for experiments analysis and for theory study. The kinetic equilibrium has the profiles information (current or safety factor profile, kinetic pressure profile), which are key issues for some studies of physics. With the constraints of magnetic measurements, pressure profile and edge current profile, we achieved the first reconstructed kinetic equilibrium on EAST tokamak. The pressure and edge current profiles are based on the diagnostics and theoretical bootstrap current model. The kinetic equilibrium has the pedestal structure for H-mode plasma, which the magnetic reconstruction missed. This improved equilibrium is an important basis for some experimental analysis and theory studies on EAST.

G Q Li; Q L Ren; J P Qian; L L Lao; S Y Ding; Y J Chen; Z X Liu; B Lu; Q Zang

2013-01-01T23:59:59.000Z

440

Kinetics of ethanol dehydrogenation into ethyl acetate  

Science Journals Connector (OSTI)

The kinetics of gas-phase dehydrogenation of ethanol into ethyl acetate over a copper-zinc- ... means to design a reactor for dehydrogenation of ethanol into ethyl acetate in different regimes.

V. A. Menshchikov; L. Kh. Goldshtein; I. P. Semenov

2014-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "kinetics laser ablation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


441

Fiber optic laser rod  

DOE Patents [OSTI]

A laser rod is formed from a plurality of optical fibers, each forming an individual laser. Synchronization of the individual fiber lasers is obtained by evanescent wave coupling between adjacent optical fiber cores. The fiber cores are dye-doped and spaced at a distance appropriate for evanescent wave coupling at the wavelength of the selected dye. An interstitial material having an index of refraction lower than that of the fiber core provides the optical isolation for effective lasing action while maintaining the cores at the appropriate coupling distance. 2 figs.

Erickson, G.F.

1988-04-13T23:59:59.000Z

442

Mechanistic studies using kinetic isotope effects  

E-Print Network [OSTI]

MECHANISTIC STUDIES USING KINETIC ISOTOPE EFFECTS A Thesis by BRIAN E. SCHULMFIER Submitted to the Office of Graduate Studies of Texas ARM University in partial fulfillment of the requtrements for the degree of MASTER OF SCIENCE December... 1999 Major Subject: Chemistry MECHANISTIC STUDIES USING KINETIC ISOTOPE EFFECTS A Thesis by BRIAN E. SCHULMEIER Submitted to Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Approved...

Schulmeier, Brian E.

2012-06-07T23:59:59.000Z

443

Kinetic decoupling of WIMPs: analytic expressions  

E-Print Network [OSTI]

We present a general expression for the values of the average kinetic energy and of the temperature of kinetic decoupling of a WIMP, valid for any cosmological model. We show an example of the usage of our solution when the Hubble rate has a power-law dependence on temperature, and we show results for the specific cases of kination cosmology and low- temperature reheating cosmology.

Visinelli, Luca

2015-01-01T23:59:59.000Z

444

Quintom scenario with mixed kinetic terms  

SciTech Connect (OSTI)

We examine an extension of the quintom scenario of dark energy, in which a canonical scalar field and a phantom field are coupled through a kinetic interaction. We perform a phase-space analysis and show that the kinetic coupling gives rise to novel cosmological behavior. In particular, we obtain both quintessence-like and phantomlike late-time solutions, as well as solutions that cross the phantom divide during the evolution of the Universe.

Saridakis, Emmanuel N. [College of Mathematics and Physics, Chongqing University of Posts and Telecommunications, Chongqing, 400065 (China); Weller, Joel M. [Department of Applied Mathematics, University of Sheffield, Hounsfield Road, Sheffield S3 7RH (United Kingdom)

2010-06-15T23:59:59.000Z

445

Laser Wakefield Particle Accelerators Project at NERSC  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Laser Wakefield Particle Acceleration Laser Wakefield Particle Acceleration Vorpal.jpg Key Challenges: Design of multiple-staged, 10-GeV laser-wakefield plasma accelerated...

446

EA-1655: Berkeley Lab Laser Accelerator (BELLA) Laser Acquisition, Installation and Use for Research and Development  

Broader source: Energy.gov [DOE]

Berkeley Lab Laser Accelerator (BELLA) Laser Acquisition, Installation and Use for Research and Development

447

Terahertz quantum cascade lasers  

E-Print Network [OSTI]

The development of the terahertz frequency range has long been impeded by the relative dearth of compact, coherent radiation sources of reasonable power. This thesis details the development of quantum cascade lasers (QCLs) ...

Williams, Benjamin S. (Benjamin Stanford), 1974-

2003-01-01T23:59:59.000Z

448

Laser Technology: Additive Manufacturing  

Science Journals Connector (OSTI)

Selective Laser Sintering, and in general Additive Manufacturing Processes are becoming mature technologies; in the ... systems that are even utilized for direct parts manufacturing. However, the parts final user...

Srichand Hinduja; Lin Li

2013-01-01T23:59:59.000Z

449

Along the Laser Beampath  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

from the master oscillator, amplifiy it more than a billion times, and set its spatial profile before injecting it into the main laser beampath. Photo Number: NIF-1107-1416113...

450

Injection Laser System  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Injection Laser System For each of NIF's 192 beams: The pulse shape as a function of time must be generated with a high degree of precision The energy delivered to the target must...

451

Spark and Laser Ignition  

Science Journals Connector (OSTI)

In the context of nonshock initiation of secondary explosives, electric sparks and lasers represent sources of external power that may stimulate exothermic reaction in energetic materials, and generate enough ...

James E. Kennedy

2010-01-01T23:59:59.000Z

452

Fusion reactor pumped laser  

DOE Patents [OSTI]

A nuclear pumped laser capable of producing long pulses of very high power laser radiation is provided. A toroidal fusion reactor provides energetic neutrons which are slowed down by a moderator. The moderated neutrons are converted to energetic particles capable of pumping a lasing medium. The lasing medium is housed in an annular cell surrounding the reactor. The cell includes an annular reflecting mirror at the bottom and an annular output window at the top. A neutron reflector is disposed around the cell to reflect escaping neutrons back into the cell. The laser radiation from the annular window is focused onto a beam compactor which generates a single coherent output laser beam. 10 figs.

Jassby, D.L.

1987-09-04T23:59:59.000Z

453

Dark Soliton Fiber Laser  

E-Print Network [OSTI]

We report on the experimental observation of stable dark solitons in an all normal dispersion fiber laser. We found experimentally that dark soliton formation is a generic feature of the fiber laser under strong continuous wave (CW) emission. However, only under appropriate pump strength and negative cavity feedback, stable single or multiple dark soliton could be achieved. Furthermore, we show that the features of the observed dark solitons could be well understood based on the nonlinear Schrodinger equation (NLSE).

H. Zhang; D. Y. Tang; L. M. Zhao; X. Wu; Q. L. Bao; K. P. Loh

2009-05-08T23:59:59.000Z

454

Insulator for laser housing  

DOE Patents [OSTI]

The present invention provides a heat-resistant electrical insulator adapted for joining laser housing portions, which insulator comprises: an annulus; a channel in the annulus traversing the circumference and length of the housing; at least two ports, each communicating with the channel and an outer surface of the housing; and an attachment for securely attaching each end of the annulus to a laser housing member.

Duncan, David B. (Auburn, CA)

1992-01-01T23:59:59.000Z

455

Variable laser attenuator  

DOE Patents [OSTI]

The disclosure relates to low loss, high power variable attenuators comprising one or more transmissive and/or reflective multilayer dielectric filters. The attenuator is particularly suitable to use with unpolarized lasers such as excimer lasers. Beam attenuation is a function of beam polarization and the angle of incidence between the beam and the filter and is controlled by adjusting the angle of incidence the beam makes to the filter or filters. Filters are selected in accordance with beam wavelength. 9 figs.

Foltyn, S.R.

1987-05-29T23:59:59.000Z

456

Laser cooling of solids  

SciTech Connect (OSTI)

We present an overview of solid-state optical refrigeration also known as laser cooling in solids by fluorescence upconversion. The idea of cooling a solid-state optical material by simply shining a laser beam onto it may sound counter intuitive but is rapidly becoming a promising technology for future cryocooler. We chart the evolution of this science in rare-earth doped solids and semiconductors.

Epstein, Richard I [Los Alamos National Laboratory; Sheik-bahae, Mansoor [UNM

2008-01-01T23:59:59.000Z

457

Insulator for laser housing  

DOE Patents [OSTI]

The present invention provides a heat-resistant electrical insulator adapted for joining laser housing portions, which insulator comprises: an annulus; a channel in the annulus traversing the circumference and length of the housing; at least two ports, each communicating with the channel and an outer surface of the housing; and an attachment for securely attaching each end of the annulus to a laser housing member. 3 figs.

Duncan, D.B.

1992-12-29T23:59:59.000Z

458

Fast surface temperature measurement of Teflon propellant-in-pulsed ablative discharges using HgCdTe photovoltaic cells  

SciTech Connect (OSTI)

High-speed mercury cadmium telluride photovoltaic detectors, sensitive to infrared emission, are investigated as a means of measuring surface temperature on a microsecond time frame during pulsed ablative discharges with Teflon trade mark sign as the ablated material. Analysis is used to derive a governing equation for detector output voltage for materials with wavelength dependent emissivity. The detector output voltage is experimentally calibrated against thermocouples embedded in heated Teflon. Experimental calibration is performed with Teflon that has been exposed to {approx}200 pulsed discharges and non-plasma-exposed Teflon and is compared to theoretical predictions to analyze emissivity differences. The diagnostic capability is evaluated with measurements of surface temperature from the Teflon propellant of electric micropulsed plasma thrusters. During the pulsed current discharge, there is insufficient information to claim that the surface temperature is accurately measured. However, immediately following the discharge, the postpulse cooling curve is measured. The statistical spread of postpulse surface temperature from shot to shot, most likely due to arc constriction and localization, is investigated to determine an operational envelope for postpulse temperature and mass ablation. This information is useful for determining postpulse ablation contributions to mass loss as well as evaluation of theoretical discharge models currently under development.

Antonsen, Erik L.; Burton, Rodney L.; Reed, Garrett A.; Spanjers, Gregory G. [University of Illinois at Urbana-Champaign, Illinois 61801 (United States); ERC Inc., Edwards AFB, California 93524 (United States); Air Force Research Laboratory, Space Vehicles Directorate, Kirtland AFB, New Mexico 87117 (United States)

2006-10-15T23:59:59.000Z

459

Total energy loss to fast ablator-ions and target capacitance of direct-drive implosions on OMEGA  

E-Print Network [OSTI]

Energetics, Rochester, New York 14623, USA 3 Los Alamos National Laboratory, Los Alamos, New Mexico 87545Total energy loss to fast ablator-ions and target capacitance of direct-drive implosions on OMEGA N 19, 093101 (2012) Target normal sheath acceleration sheath fields for arbitrary electron energy

460

22nd IAEA-FEC Kinetic theory of Geodesic Acoustic Modes: ... 1 Kinetic theory of Geodesic Acoustic  

E-Print Network [OSTI]

22nd IAEA-FEC Kinetic theory of Geodesic Acoustic Modes: ... 1 Kinetic theory of Geodesic Acoustic Zonca, Liu Chen and Zhiyong Qiu #12;22nd IAEA-FEC Kinetic theory of Geodesic Acoustic Modes: ... 2 Chen and Zhiyong Qiu #12;22nd IAEA-FEC Kinetic theory of Geodesic Acoustic Modes: ... 3 2 Linear

Zonca, Fulvio

Note: This page contains sample records for the topic "kinetics laser ablation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


461

CRC handbook of laser science and technology. Volume 3. Gas lasers  

SciTech Connect (OSTI)

This book describes the fundamentals of gas lasers. It provides information and data on neutral gas lasers, ionized gas lasers, and molecular gas lasers. Concluding this volume is an extensive table of all gas laser wavelengths.

Weber, M.J.

1982-01-01T23:59:59.000Z

462

Titanium monoxide spectroscopy following laser-induced optical breakdown  

SciTech Connect (OSTI)

This work investigates Titanium Monoxide (TiO) in ablation-plasma by employing laser-induced breakdown spectroscopy (LIBS) with 1 to 10 TW/cm{sup 2} irradiance, pulsed, 13 nanosecond, Q-switched Nd:YAG laser radiation at the fundamental wavelength of 1064 nm. The analysis of TiO is based on our first accurate determination of transition line strengths for selected TiO A-X, B-X, and E-X transitions, particularly TiO A-X {gamma} and B-X {gamma} Prime bands. Electric dipole line strengths for the A{sup 3}{Phi}-X{sup 3}{delta} and B{sup 3}{Pi}-X{sup 3}{delta} bands of TiO are computed. The molecular TiO spectra are observed subsequent to laser-induced breakdown (LIB). We discuss analysis of diatomic molecular spectra that may occur simultaneously with spectra originating from atomic species. Gated detection is applied to investigate the development in time of the emission spectra following LIB. Collected emission spectra allow one to infer micro-plasma parameters such as temperature and electron density. Insight into the state of the micro-plasma is gained by comparing measurements with predictions of atomic and molecular spectra. Nonlinear fitting of recorded and computed diatomic spectra provides the basis for molecular diagnostics, while atomic species may overlap and are simultaneously identified. Molecular diagnostic approaches similar to TiO have been performed for diatomic molecules such as AlO, C{sub 2}, CN, CH, N{sub 2}, NH, NO and OH.

Parigger, Christian G.; Woods, Alexander C.; Keszler, Anna; Nemes, Laszlo; Hornkohl, James O. [The University of Tennessee/UT Space Institute, Center for Laser Applications, 411 B.H. Goethert Parkway, Tullahoma, TN 37388-9700 (United States); Chemical Research Center of the Hungarian Academy of Sciences, Institute of Materials and Environmental Chemistry, Pusztaszeri ut 59-67, H-1025 Budapest (Hungary); Chemical Research Center of the Hungarian Academy of Sciences, Laser Spectroscopy Laboratory, Pusztaszeri ut 59-67, H-1025 Budapest (Hungary); Hornkohl Consulting, Tullahoma, TN 37388 (United States)

2012-07-30T23:59:59.000Z

463

Laser-driven acceleration of a dense matter up to 'thermonuclear' velocities  

Science Journals Connector (OSTI)

The results of theoretical studies and numerical simulations of laser-driven acceleration of a flat foil up to ultrahigh velocity of the order of 1000?km?s?1, which corresponds to the achievement of thermonuclear temperatures due to kinetic energy transition into thermal energy at an inelastic impact, are reported. The behavior of a foil accelerated to such high velocities, in particular, the distribution of foil density, which defines thermonuclear reaction intensity, has been studied. The calculation results are compared with the results of the experiments performed on the Gekko/HIPER laser, where a laser-driven projectile achieved record-breaking velocity. The laser pulse and foil parameters responsible for acceleration of the projectile up to 'thermonuclear' velocities in a dense state have been determined.

S Yu Gus'kov; H Azechi; N N Demchenko; V V Demchenko; I Ya Doskoch; M Murakami; H Nagatomo; V B Rozanov; S Sakaiya; R V Stepanov; N V Zmitrenko

2007-01-01T23:59:59.000Z

464

Optimizing conversion efficiency and reducing ion energy in a laser-produced Gd plasma  

SciTech Connect (OSTI)

We have demonstrated an efficient extreme ultraviolet (EUV) source at 6.7 nm by irradiating Gd targets with 0.8 and 1.06 {mu}m laser pulses of 140 fs to 10 ns duration. Maximum conversion efficiency of 0.4% was observed within a 0.6% bandwidth. A Faraday cup observed ion yield and time of flight signals for ions from plasmas generated by each laser. Ion kinetic energy was lower for shorter pulse durations, which yielded higher electron temperatures required for efficient EUV emission, due to higher laser intensity. Picosecond laser pulses were found to be the best suited to 6.7 nm EUV source generation.

Cummins, Thomas; Li Bowen; O'Gorman, Colm; Dunne, Padraig; Sokell, Emma; O'Sullivan, Gerry [School of Physics, University College Dublin, Belfield, Dublin 4 (Ireland); Otsuka, Takamitsu [Department of Advanced Interdisciplinary Sciences, Center for Optical Research and Education (CORE), and Optical Technology Innovation Center (OpTIC), Utsunomiya University, Yoto 7-1-2, Utsunomiya, Tochigi 321-8585 (Japan); Yugami, Noboru; Higashiguchi, Takeshi [Department of Advanced Interdisciplinary Sciences, Center for Optical Research and Education (CORE), and Optical Technology Innovation Center (OpTIC), Utsunomiya University, Yoto 7-1-2, Utsunomiya, Tochigi 321-8585 (Japan); Japan Science and Technology Agency, CREST, 4-1-8 Honcho, Kanagawa, Saitama 332-0012 (Japan); Jiang Weihua [Department of Electrical Engineering, Nagaoka University of Technology, Kami-tomiokamachi 1603-1, Nagaoka, Niigata 940-2188 (Japan); Endo, Akira [Research Institute for Science and Engineering, Waseda University, Okubo 3-4-1, Shinjuku, Tokyo 169-8555 (Japan)

2012-02-06T23:59:59.000Z

465

Hydrodynamic simulations of long-scale-length two-plasmon-decay experiments at the Omega Laser Facility  

SciTech Connect (OSTI)

Direct-drive-ignition designs with plastic CH ablators create plasmas of long density scale lengths (L{sub n} {>=} 500 {mu}m) at the quarter-critical density (N{sub qc}) region of the driving laser. The two-plasmon-decay (TPD) instability can exceed its threshold in such long-scale-length plasmas (LSPs). To investigate the scaling of TPD-induced hot electrons to laser intensity and plasma conditions, a series of planar experiments have been conducted at the Omega Laser Facility with 2-ns square pulses at the maximum laser energies available on OMEGA and OMEGA EP. Radiation-hydrodynamic simulations have been performed for these LSP experiments using the two-dimensional hydrocode draco. The simulated hydrodynamic evolution of such long-scale-length plasmas has been validated with the time-resolved full-aperture backscattering and Thomson-scattering measurements. draco simulations for CH ablator indicate that (1) ignition-relevant long-scale-length plasmas of L{sub n} approaching {approx}400 {mu}m have been created; (2) the density scale length at N{sub qc} scales as L{sub n}({mu}m) Asymptotically-Equal-To (R{sub DPP} Multiplication-Sign I{sup 1/4}/2); and (3) the electron temperature T{sub e} at N{sub qc} scales as T{sub e}(keV) Asymptotically-Equal-To 0.95 Multiplication-Sign {radical}(I), with the incident intensity (I) measured in 10{sup 14} W/cm{sup 2} for plasmas created on both OMEGA and OMEGA EP configurations with different-sized (R{sub DPP}) distributed phase plates. These intensity scalings are in good agreement with the self-similar model predictions. The measured conversion fraction of laser energy into hot electrons f{sub hot} is found to have a similar behavior for both configurations: a rapid growth [f{sub hot} Asymptotically-Equal-To f{sub c} Multiplication-Sign (G{sub c}/4){sup 6} for G{sub c} < 4] followed by a saturation of the form, f{sub hot} Asymptotically-Equal-To f{sub c} Multiplication-Sign (G{sub c}/4){sup 1.2} for G{sub c} {>=} 4, with the common wave gain is defined as G{sub c}=3 Multiplication-Sign 10{sup -2} Multiplication-Sign I{sub qc}L{sub n}{lambda}{sub 0}/T{sub e}, where the laser intensity contributing to common-wave gain I{sub qc}, L{sub n}, T{sub e} at N{sub qc}, and the laser wavelength {lambda}{sub 0} are, respectively, measured in [10{sup 14} W/cm{sup 2}], [{mu}m], [keV], and [{mu}m]. The saturation level f{sub c} is observed to be f{sub c} Asymptotically-Equal-To 10{sup -2} at around G{sub c} Asymptotically-Equal-To 4. The hot-electron temperature scales roughly linear with G{sub c}. Furthermore, to mitigate TPD instability in long-scale-length plasmas, different ablator materials such as saran and aluminum have been investigated on OMEGA EP. Hot-electron generation has been reduced by a factor of 3-10 for saran and aluminum plasmas, compared to the CH case at the same incident laser intensity. draco simulations suggest that saran might be a better ablator for direct-drive-ignition designs as it balances TPD mitigation with an acceptable hydro-efficiency.

Hu, S. X.; Michel, D. T.; Edgell, D. H.; Froula, D. H.; Follett, R. K.; Goncharov, V. N.; Myatt, J. F.; Skupsky, S.; Yaakobi, B. [Laboratory for Laser Energetics, University of Rochester, 250 E. River Road, Rochester, New York 14623 (United States)

2013-03-15T23:59:59.000Z

466

7-Gate Kinetic AMPA Model Kinetics to match EPSCs from calyx of Held  

E-Print Network [OSTI]

7-Gate Kinetic AMPA Model · Kinetics to match EPSCs from calyx of Held · Multiple closed, open and EPSC amplitude Bruce Graham Department of Computing Science and Mathematics, University of Stirling, U, including the calyx of Held in the mammalian auditory system. Such depression may be mediated

Graham, Bruce

467

Z .Applied Surface Science 127129 1998 142150 Computer simulation study of damage and ablation of submicron  

E-Print Network [OSTI]

irradiation regimes. It is difficult to account for these complex and interrelated processes within a single analytical continuum description. An alternative method of microscopic analysis of laser induced processes

Zhigilei, Leonid V.

468

Injection-controlled laser resonator  

DOE Patents [OSTI]

A new injection-controlled laser resonator incorporates self-filtering and self-imaging characteristics with an efficient injection scheme. A low-divergence laser signal is injected into the resonator, which enables the injection signal to be converted to the desired resonator modes before the main laser pulse starts. This injection technique and resonator design enable the laser cavity to improve the quality of the injection signal through self-filtering before the main laser pulse starts. The self-imaging property of the present resonator reduces the cavity induced diffraction effects and, in turn, improves the laser beam quality. 5 figs.

Chang, J.J.

1995-07-18T23:59:59.000Z

469

Blue-green upconversion laser  

DOE Patents [OSTI]

A blue-green laser (450--550 nm) uses a host crystal doped with Tm[sup 3+]. The Tm[sup 3+] is excited through upconversion by a red pumping laser and an IR pumping laser to a state which transitions to a relatively lower energy level through emissions in the blue-green band, e.g., 450.20 nm at 75 K. The exciting laser may be tunable dye lasers or may be solid-state semiconductor laser, e.g., GaAlAs and InGaAlP. 3 figs.

Nguyen, D.C.; Faulkner, G.E.

1990-08-14T23:59:59.000Z

470

Blue-green upconversion laser  

DOE Patents [OSTI]

A blue-green laser (450-550 nm) uses a host crystal doped with Tm.sup.3+. The Tm.sup.+ is excited through upconversion by a red pumping laser and an IR pumping laser to a state which transitions to a relatively lower energy level through emissions in the blue-green band, e.g., 450.20 nm at 75 K. The exciting laser may be tunable dye lasers or may be solid-state semiconductor laser, e.g., GaAlAs and InGaAlP.

Nguyen, Dinh C. (Los Alamos, NM); Faulkner, George E. (Los Alamos, NM)

1990-01-01T23:59:59.000Z

471

Chemical Kinetic Modeling of Advanced Transportation Fuels  

SciTech Connect (OSTI)

Development of detailed chemical kinetic models for advanced petroleum-based and nonpetroleum based fuels is a difficult challenge because of the hundreds to thousands of different components in these fuels and because some of these fuels contain components that have not been considered in the past. It is important to develop detailed chemical kinetic models for these fuels since the models can be put into engine simulation codes used for optimizing engine design for maximum efficiency and minimal pollutant emissions. For example, these chemistry-enabled engine codes can be used to optimize combustion chamber shape and fuel injection timing. They also allow insight into how the composition of advanced petroleum-based and non-petroleum based fuels affect engine performance characteristics. Additionally, chemical kinetic models can be used separately to interpret important in-cylinder experimental data and gain insight into advanced engine combustion processes such as HCCI and lean burn engines. The objectives are: (1) Develop detailed chemical kinetic reaction models for components of advanced petroleum-based and non-petroleum based fuels. These fuels models include components from vegetable-oil-derived biodiesel, oil-sand derived fuel, alcohol fuels and other advanced bio-based and alternative fuels. (2) Develop detailed chemical kinetic reaction models for mixtures of non-petroleum and petroleum-based components to represent real fuels and lead to efficient reduced combustion models needed for engine modeling codes. (3) Characterize the role of fuel composition on efficiency and pollutant emissions from practical automotive engines.

PItz, W J; Westbrook, C K; Herbinet, O

2009-01-20T23:59:59.000Z

472

Variable emissivity laser thermal control system  

DOE Patents [OSTI]

A laser thermal control system for a metal vapor laser maintains the wall mperature of the laser at a desired level by changing the effective emissivity of the water cooling jacket. This capability increases the overall efficiency of the laser.

Milner, Joseph R. (Livermore, CA)

1994-01-01T23:59:59.000Z

473

Dynamic Stabilization of the Ablative Rayleigh-Taylor Instability for Heavy Ion Fusion  

SciTech Connect (OSTI)

Dynamic stabilization of the ablative Rayleigh-Taylor instability of a heavy ion fusion target induced by a beam wobbling system is studied. Using a sharp-boundary model and Courant-Synder theory, it is shown, with an appropriately chosen modulation waveform, that the instability can be sta- bilized in certain parameter regimes. It is found that the stabilization e ect has a strong dependence on the modulation frequency and the waveform. Modulation with frequency comparable to the instability growth rate is the most e ective in terms of stabilizing the instability. A modulation with two frequency components can result in a reduction of the growth rate larger than the sum of that due to the two components when applied separately.

Hong Qin, Ronald C. Davidson and B. Grant Logan

2012-10-04T23:59:59.000Z

474

Evidence for ablated flows in the shell of nova DQ Her  

E-Print Network [OSTI]

High-resolution longslit Halpha spectra of the shell of the old nova DQ Her have been obtained with the William Herschel Telescope using the ISIS spectrograph. An equatorial expansion velocity of 370+/-14 km/s is derived from the spectra which, in conjunction with a narrowband Halpha image of the remnant, allows a distance estimate of 525+/-28 pc. An equatorial ring which exhibits enhanced [NII] emission has also been detected and the inclination angle of the shell is found to be 86.8+/-0.2 degrees with respect to the line of sight. The spectra also reveal tails extending from the clumps in the shell, which have a radial velocity increasing along their length. This suggests the presence of a stellar wind, collimated in the polar direction, which ablates fragments of material from the clumps and accelerates them into its stream up to a terminal velocity of order 800-900 km/s.

N. M. H. Vaytet; T. J. O'Brien; A. P. Rushton

2007-06-01T23:59:59.000Z

475

Entrained-Flow, Fast Ablative Pyrolysis of Biomass - Annual Report, 1 December 1984 - 31 December 1985  

SciTech Connect (OSTI)

The ablative, fast pyrolysis system was relocated to SERI's new, permanent Field Test Laboratory. Pyrolysis system modifications were made to increase the energy available to the vortex reactor and to enhance the collection efficiency of primary pyrolysis vapors. Mathematical modeling of the vapor cracker has resulted in the ability to accurately predict experimental results with respect to the thermal cracking of the primary vapors, the generation of noncondensible gases, and the gas composition. The computer algorithm of this model can be readily used to perform experimental simulation and/or reactor scale-up due to its fundamental nature. Preliminary screening tests with pure ZSM-5 zeolite catalyst, supplied by Mobil Research and Development Corporation, have shown promise for the conversion of primary pyrolysis oil vapors to aromatic hydrocarbons; i.e., gasoline.

Diebold, J. P.; Scahill, J. W.; Evans, R. J.

1986-07-01T23:59:59.000Z

476

History of Gas Lasers, Part 2: Pulsed Gas Lasers  

Science Journals Connector (OSTI)

In this second article of a two-part series, Colin Webb explores the origins of pulsed gas lasers, which made possible many critical applications of laser technology, including...

Webb, Colin

2010-01-01T23:59:59.000Z

477

OMEGA EP Laser Sources - Laboratory for Laser Energetics  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Sources - Laboratory for Laser Energetics Laboratory for Laser Energetics Logo Search Home Around the Lab Past Issues Past Quick Shots About Office of the Director Map to LLE LLE...

478

Omega Laser Facility Schedule - Laboratory for Laser Energetics  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Schedule - Laboratory for Laser Energetics Laboratory for Laser Energetics Logo Search Home Around the Lab Past Issues Past Quick Shots About Office of the Director Map to LLE LLE...

479

Nonlinear laser energy depletion in laser-plasma accelerators  

E-Print Network [OSTI]

Lee- mans, in Advanced Accelerator Concepts, Eleventh Work-in laser-plasma accelerators ? B. A. Shadwick, 1, C. B.ac- celerators. Laser-plasma accelerators, for example, have

Shadwick, B.A.

2009-01-01T23:59:59.000Z

480

Laser Guiding for GeV Laser-Plasma Accelerators  

E-Print Network [OSTI]

Overview of plasma-based accelerator concepts. IEEE Trans.using laser wake?eld accelerators. Meas. Sci. Technol. 12,for GeV laser-plasma accelerators. In Advanced Accelerator

Leemans, Wim; Esarey, Eric; Geddes, Cameron; Schroeder, C.B.; Toth, Csaba

2005-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "kinetics laser ablation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


481

Controlling molecules with lasers and lasers with molecules  

E-Print Network [OSTI]

I investigate quantum control of spin in molecules using shaped ultrafast lasers and the dynamics of those lasers when their cavities are modified to include programmable molecular masks. The ability to control quantum ...

Taylor, Jason Matthew, 1977-

2007-01-01T23:59:59.000Z

482

Modeling of laser cladding with diode laser robotized system  

Science Journals Connector (OSTI)

The choice of proper working conditions is a problem for any processing. But for laser processing this procedure is much more serious. ... modeling is accepted. The actual model for laser cladding is developed ba...

Jianhua Yao; V. S. Kovalenko; Qunli Zhang

2010-06-01T23:59:59.000Z

483

Melt-solid interactions in laser cladding and laser casting  

Science Journals Connector (OSTI)

Experimental data in conjunction with mathematical models are used to explain various aspects of laser casting and laser cladding by the preplaced powder method. For increasing ... the powder bed is analyzed to i...

H. Gedda; A. Kaplan; J. Powell

2005-10-01T23:59:59.000Z

484

Other Projects [Laser Applications Laboratory] - Nuclear Engineering  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Other Projects Other Projects Capabilities Engineering Experimentation Reactor Safety Experimentation Aerosol Experiments System Components Laser Applications Overview Laser Oil & Gas Well Drilling Laser Heat Treatment Laser Welding of Metals On-line Monitoring Laser Beam Delivery Laser Glazing of Railroad Rails High Power Laser Beam Delivery Decontamination and Decommissioning Refractory Alloy Welding Robots Applications Other Facilities Other Capabilities Work with Argonne Contact us For Employees Site Map Help Join us on Facebook Follow us on Twitter NE on Flickr Laser Applications Laboratory Other projects Bookmark and Share HIGH POWER LASER BEAM DELIVERY High-power laser-beam delivery with conventional and fiber optics DECONTAMINATION & DECOMMISSIONING Laser processing technology for decontamination of surfaces

485

Philips Color Kinetics | Open Energy Information  

Open Energy Info (EERE)

Color Kinetics Color Kinetics Jump to: navigation, search Name Philips Color Kinetics Address 3 Burlington Woods Drive, 4th Floor Place Burlington, Massachusetts Zip 01803 Sector Efficiency Product LED lighting systems Website http://www.colorkinetics.com/ Coordinates 42.5005723°, -71.2042619° Loading map... {"minzoom":false,"mappingservice":"googlemaps3","type":"ROADMAP","zoom":14,"types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"geoservice":"google","maxzoom":false,"width":"600px","height":"350px","centre":false,"title":"","label":"","icon":"","visitedicon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"wmsoverlay":"","layers":[],"controls":["pan","zoom","type","scale","streetview"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"kml":[],"gkml":[],"fusiontables":[],"resizable":false,"tilt":0,"kmlrezoom":false,"poi":true,"imageoverlays":[],"markercluster":false,"searchmarkers":"","locations":[{"text":"","title":"","link":null,"lat":42.5005723,"lon":-71.2042619,"alt":0,"address":"","icon":"","group":"","inlineLabel":"","visitedicon":""}]}

486

Laser Facilities, Laser-Plasmas & Diagnostics Plasmas Division  

E-Print Network [OSTI]

of freely moving ions and free electrons. Figure 1: The large NOVA laser at Lawrence Livermore National Facility (NIF) is the world's largest and highest-energy laser (Figure 2). It houses 192 intense laser and of a single wavelength. There are a large number of Figure 2: NIF from above & the target chamber. Figure 4

Strathclyde, University of

487

[Laser flash photolysis, EPR and Raman studies of liquids at elevated pressures  

SciTech Connect (OSTI)

The proposed research will solve a number of analytical chemical problems in solutions with measurement techniques that benefit from the use of elevated hydrostatic pressures: stopped-flow spectrophotometry (Gd[sup 3+] + L(ligand), [RuL[sub 5]H[sub 2]O][sup 2+], laser flash photolysis of Mo(CO)[sub 6] + L, flash photolysis of binuclear metalloproteins), EPR spectroscopy (Gd[sup 3+] ion-exchanged into ETS-10 and ETAS-10 molecular sieves), laser flash photolysis kinetic studies of Mo(CO)[sub 6]-2,2'-bipyridine, and electrochemical studies of metalloporphyrins using resonance Raman spectroscopy.

Eyring, E.M.

1992-01-01T23:59:59.000Z

488

[Laser flash photolysis, EPR and Raman studies of liquids at elevated pressures  

SciTech Connect (OSTI)

The proposed research will solve a number of analytical chemical problems in solutions with measurement techniques that benefit from the use of elevated hydrostatic pressures: stopped-flow spectrophotometry (Gd{sup 3+} + L(ligand), [RuL{sub 5}H{sub 2}O]{sup 2+}, laser flash photolysis of Mo(CO){sub 6} + L, flash photolysis of binuclear metalloproteins), EPR spectroscopy (Gd{sup 3+} ion-exchanged into ETS-10 and ETAS-10 molecular sieves), laser flash photolysis kinetic studies of Mo(CO){sub 6}-2,2`-bipyridine, and electrochemical studies of metalloporphyrins using resonance Raman spectroscopy.

Eyring, E.M.

1992-10-01T23:59:59.000Z

489

LASER SAFETY MANUAL POLICIES AND PROCEDURES  

E-Print Network [OSTI]

LASER SAFETY MANUAL POLICIES AND PROCEDURES FOR LASER SAFETY AT TEXAS TECH UNIVERSITY LUBBOCK, TEXAS September 2002 #12;V-1 TEXAS TECH UNIVERSITY LASER SAFETY MANUAL TABLE OF CONTENTS SECTION I ­ MANAGEMENT OF LASER LICENSE Introduction A. Laser Safety Program I - 1 B. Radiation Laser Safety Committee I

Zhang, Yuanlin

490

Kinetic studies of elementary chemical reactions  

SciTech Connect (OSTI)

This program concerning kinetic studies of elementary chemical reactions is presently focussed on understanding reactions of NH{sub x} species. To reach this goal, the author is pursuing experimental studies of reaction rate coefficients and product branching fractions as well as using electronic structure calculations to calculate transition state properties and reaction rate calculations to relate these properties to predicted kinetic behavior. The synergy existing between the experimental and theoretical studies allow one to gain a deeper insight into more complex elementary reactions.

Durant, J.L. Jr. [Sandia National Laboratories, Livermore, CA (United States)

1993-12-01T23:59:59.000Z

491

The Laser as a Weapon  

Science Journals Connector (OSTI)

The laser beam is popularly thought of as a very powerful death ray which can be fired from a hand-held laser gun to vaporize soldiers, demolish buildings, and burn through tanks. This is an immense exaggeration ...

Major General Bengt Anderberg; Dr. Myron L. Wolbarsht

1992-01-01T23:59:59.000Z

492

BNL | Nd:YAG Laser  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

gun.The Nd:YAg laser is operated in a power amplifier mode, giving it a unique Pulse Train Mode. For certain experiments, like the FEL Oscillator Experiment, the YAG laser can...

493

Laser Additive Manufacturing of Metals  

Science Journals Connector (OSTI)

Laser Additive Manufacturing (LAM) is based on a repeating layer wise manufacturing process which uses a laser beam to ... ) geometries into simpler two-dimensional (2D) manufacturing steps [1, 2...]. Thus LAM of...

Claus Emmelmann; Jannis Kranz; Dirk Herzog; Eric Wycisk

2013-01-01T23:59:59.000Z

494

Solid Solubility in Laser Cladding  

Science Journals Connector (OSTI)

Laser cladding techniques have recently enjoyed attention in preparing ... solid solution formed due to rapid cooling in laser cladding. This model considers a diffusion mechanism for ... one-dimensional semi-inf...

J. Mazumder; A. Kar

1987-02-01T23:59:59.000Z

495

Hybrid laser with CMOS photonics  

E-Print Network [OSTI]

In this thesis, an interesting approach for a photonic laser source is presented. By using integrated photonic resonators with an external gain medium, we are able to build a laser that offers a number of advantages including ...

Chong, Johanna S

2014-01-01T23:59:59.000Z

496

Self-tuning method for monitoring the density of a gas vapor component using a tunable laser  

DOE Patents [OSTI]

The present invention relates to a vapor density monitor and laser atomic absorption spectroscopy method for highly accurate, continuous monitoring of vapor densities, composition, flow velocity, internal and kinetic temperatures and constituent distributions. The vapor density monitor employs a diode laser, preferably of an external cavity design. By using a diode laser, the vapor density monitor is significantly less expensive and more reliable than prior art va